Diagnostics of faults in vehicle components and systems (Honda Civic 6)

Vehicle owners who perform routine vehicle maintenance procedures as described in Chapter Routine maintenance of this Manual, the schedule will very rarely have to refer to the materials of this Section. The reliability of units and components installed on modern cars is so high that with timely replacement of worn out and failed parts due to aging of materials, the probability of their sudden failure is extremely small. Failures rarely occur spontaneously and are usually a consequence of sometimes prolonged development of a defect. In particular, the failure of mechanical components is almost always preceded by the emergence and evolution of characteristic symptoms, sometimes manifesting themselves many thousands of kilometers before failure. The same components that can fail unexpectedly are usually not vital for the functioning of the main units and systems of the car, or are easily replaced under road conditions. The fundamental step in identifying the causes of any failure is choosing the starting point for searching. Often the cause is obvious, but in some cases you have to work hard, conducting a small investigation. A car enthusiast who has made half a dozen random checks, replacements and corrections has a good chance of discovering the cause of the failure (or its symptom), however, this approach cannot be called reasonable in any way, due to its labor intensity and the pointlessness of time and money spent. A calm, logical approach to finding a failed unit or component is much more effective. It is imperative to take into account all the symptoms and warning signs that preceded the breakdown, sometimes minor ones, such as loss of engine power, changes in meter readings, the occurrence of unusual sounds and smells, etc. Do not forget that the failure of components such as fuses or spark plugs may be only a symptom of a more deeply hidden problem.



Below in this subsection is a fairly simple diagnostic scheme for the most common failures. The causes of failures and their symptoms are grouped according to their relation to the functioning of a specific unit or system: "Engine", "Cooling system", etc.

Regardless of the nature of the failure, the same basic principles always form the basis for investigating its cause:

• Make sure you have correctly identified the symptoms of the failure. This means being sure that you have defined the boundaries of the search area, which is especially important when helping another motorist diagnose a failure who cannot adequately describe the symptoms of the problem.
• Try not to overlook obvious violations. For example, if the engine does not start, do not hesitate to check the fuel level in the gas tank (however, one should not take the claims of the owner of a faulty car at face value). In the event of electrical equipment failure, the first thing to check is the condition and reliability of the electrical wiring terminal connections; only after that does it make sense to get out the diagnostic devices.
• Try to eliminate the cause of the failure, not its symptom. Replacing a discharged battery with a new one will help start the engine, but the existing cause of the old battery discharge will remain unresolved, which will lead to the rapid failure of the new one. Similarly, replacing spark plugs covered in oil will restore the engine's functionality for a while, but the failure will certainly reoccur soon (if the reason was not simply the use of the wrong type of candles).
• Don't take any statements at face value! Remember that a recently installed "new" component may also be faulty, especially if it has been lying in the trunk for a long time - do not exclude a component from the list of checks just because it is new or recently installed. If you neglect to follow this recommendation, do not be surprised when the cause of the failure is finally revealed to be obvious from the very beginning.

Diagnostics of failures and reasons for the decrease in engine efficiency

The engine does not turn over when trying to start it

• The ignition switch is faulty.
• The battery terminals are oxidized, or the wire tips are loose.
• The battery is low or faulty.
• The charging system is not functioning properly.
• The wiring of the starting system circuit is broken or otherwise damaged, or the fastening of the contact connection terminals is loose.
• The traction relay or starter switch is out of order.
• The starter motor is faulty.
• The teeth of the starter drive pinion or flywheel ring gear are broken or worn.
• The starter drive pinion is jammed in the flywheel ring gear.
• The start enable switch sensor is faulty (models with AT) or starter circuit breaker switch sensor (models with manual transmission)
• AT is not moved to position "P" or "N".
• The engine is seized (the crankshaft or camshaft is jammed, or one of the pistons is stuck on the wall of its cylinder), - try to turn it manually using the crankshaft pulley bolt.

The engine turns over but does not start

• The fuel tank is empty.
• The battery is discharged (the engine turns over too slowly).
• The battery terminals are oxidized, or the wire tips are loose.
• The starter is faulty.
• The fuel lines are clogged, the fuel pump is faulty, or the fuel tank ventilation pipes are blocked.
• The cylinder head cover mounting bolts have become loose or its sealing gasket is damaged.
• The valves are burnt out, or the tightness of their pressure against the seats is impaired.
• The valve stem is damaged.
• The valve spring is worn out or broken.
• Valve clearance adjustment is incorrect.
• Piston rings are worn out or burnt out.
• The compression pressure has dropped or is unevenly distributed between the engine cylinders.
• Moisture has entered the fuel.
• Unsuitable oil is used (low viscosity)
• The fuel injector is faulty.
• Ignition system components are wet or damaged.
• The ignition system is not functioning properly.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The ignition timing angle setting is incorrect.
• The ignition system wiring is broken or otherwise damaged, the terminals of the contact connections are loose, or the ignition coil is faulty.
• As a result of wear of the timing drive components, the valve timing settings are disrupted.
• The timing belt/chain is broken or its tension has weakened.

Difficulty starting a cold engine

• The battery is low.
• The battery terminals are oxidized, or the wire tips are loose.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The fuel supply system is faulty.
• There are fuel leaks through the injector.
• The compression pressure has dropped.

Difficulty starting a hot engine

• The air purifier filter element is dirty or its flow is otherwise impaired.
• The fuel supply system is faulty (fuel is not supplied to the injectors).
• The battery terminal connections are oxidized (especially the mass).
• The quality of the grounding of the power unit is impaired.
• The fuel supply system or engine control system is not functioning properly.
• The fuel evaporative emission (EVAP) system is not functioning properly.
• The compression pressure has dropped.

The starter is difficult to engage or is accompanied by extraneous noises

• The teeth of the starter drive gear or flywheel ring gear are broken or worn.
• The starter mounting bolts have come loose or fallen out.
• The internal components of the starter are worn or damaged.

The engine starts but immediately stalls

• The ignition system wiring is broken or otherwise damaged, or the terminal connections on the ignition module or generator are loose.
• There is fuel starvation of the injector.
• The air cleaner filter element is dirty.
• There are losses of vacuum.
• The idle speed setting is incorrect.
• There are intake air leaks or the vacuum lines are damaged.
• Valve clearance adjustment is incorrect.
• Unsuitable oil is used (low viscosity).
• The compression pressure has dropped or is unevenly distributed between the engine cylinders.
• The ignition timing angle setting is incorrect.
• The valve timing settings are disrupted as a result of wear of the timing drive components.

During parking, oil leaks form under the engine

• There are leaks through the oil pan gasket or drain plug.
• There are leaks through the oil pressure switch sensor seat seal.
• There are leaks through the cylinder head gasket.
• There are leaks through the engine shaft seals.
• There are leaks in the oil pump.

Idle speed stability is impaired

• There are losses of vacuum.
• The exhaust gas recirculation (EGR) valve is faulty.
• The crankcase ventilation (PCV) valve is clogged.
• The air cleaner filter element is blocked.
• The fuel pump does not provide the required fuel flow.
• The cylinder head gasket is leaking.
• The timing drive components are worn out.
• The working projections of the camshaft cams are worn out.
• Valve clearance adjustment is incorrect.
• The valves are burnt out or do not fit tightly into their seats.
• The ignition timing angle setting is incorrect.
• The ignition system is not functioning properly.
• The thermostatic air purifier is not functioning properly.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The compression pressure has dropped or is unevenly distributed between the cylinders.
• The fuel injector patency is impaired.
• The idle speed setting is incorrect.

There are misfires at idle speed

• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The spark plug high voltage wires are faulty.
• Ignition system components are wet or damaged.
• There is a short circuit in the ignition circuit.
• The quality of the contact connections of the high-voltage wires is damaged, or the ignition module is faulty.
• The ignition coil is faulty.
• The components of the toxicity reduction system are faulty, or the patency of the corresponding tract is impaired.
• There are leaks in the EGR valve.
• The fuel filter is clogged or the fuel is contaminated.
• There are losses of vacuum.
• The idle speed or mixture quality settings are incorrect.
• The ignition timing angle setting is incorrect.
• The compression pressure has dropped or is unevenly distributed between the cylinders.
• There are losses of vacuum in the intake manifold or through the connecting vacuum hoses.
• The fuel injectors are not flowing properly.

Misfires occur when driving in gear

• The fuel filter/connection line of the fuel system is clogged.
• The fuel pressure has dropped.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The ignition timing angle setting is incorrect.
• The reliability of the fastening of the contact connections of the high-voltage wires is compromised, or the ignition module is faulty.
• There is a "breakdown" in the electrical wiring of the high-voltage spark plug wires.
• Components of the exhaust gas toxicity reduction systems are faulty.
• The compression pressure has dropped or is unevenly distributed between the cylinders.
• The ignition system is faulty, or the contact connections of its electrical wiring are loose.
• There are losses of vacuum.
• The fuel pump is faulty, or the pressure it produces has dropped.
• The fuel tank ventilation is broken.

Idle speed is too high

• The smoothness of the throttle drive is impaired.
• The idle speed setting is incorrect.
• There are leaks in the air intake tract.
• The engine management system is not functioning properly.

The battery does not hold a charge

• The generator drive belt is worn out or its tension adjustment is not correct.
• The terminals are oxidized, or the wire tips are loosened.
• The electrolyte level in the cans has dropped.
• The generator does not produce the required charging current.
• The wiring of the charging system circuit is broken or otherwise damaged, or the fastening of the terminals of the contact connections is loose.
• The battery is discharged due to a short circuit in the on-board electrical wiring.
• There is an internal battery defect.

The charge indicator lamp remains on when the engine is running

• There is an internal defect in the generator or voltage regulator.
• The generator drive belt is worn out or broken, or its tension adjustment is not correct.
• The generator brushes are worn, jammed or dirty.
• The generator brush springs are weak or broken.
• The charging circuit wiring is broken or the terminal connections are loose.

The charge indicator lamp does not light when the key is turned to the ON position

• The filament burned out.
• The instrument cluster printed circuit board or lamp holder is faulty.
• The generator is faulty.

Engine speed stability is disrupted during acceleration

• The ignition system is not functioning properly.
• The ignition timing angle setting is incorrect.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The fuel filter is clogged.
• The fuel injectors are not flowing properly.
• The fuel pressure has dropped as a result of a malfunction of the fuel pump or a blockage in the fuel lines.
• The injectors or engine management system are not functioning properly.
• The fuel injector wiring connector has become loose.
• There are air leaks in the intake tract.
• The EGR system is not functioning properly.

The engine runs jerkily when the accelerator pedal is held motionless

• There are air leaks in the intake tract.
• The fuel pump or fuel pressure regulator is faulty.
• The fuel injector wiring connector has become loose.
• There are malfunctions in the engine management system.

The engine stalls spontaneously

• The idle speed setting is incorrect.
• The fuel filter is clogged or moisture has entered the fuel system.
• Ignition system components are wet or damaged.
• Components of the exhaust gas toxicity reduction systems are faulty.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The spark plug high voltage wires are faulty.
• There are losses of vacuum at the throttle body, intake manifold or through connecting hoses.
• Valve clearance adjustment is incorrect.
• The fuel pump is faulty, or the pressure it produces has dropped.
• The ventilation of the fuel tank is broken or the fuel lines are blocked.
• The injection system or engine management system is not functioning properly.

The engine power has dropped

• The crankcase ventilation hose is damaged.
• The vacuum hose is damaged.
• The intake manifold gasket is damaged.
• The ignition timing angle setting is incorrect.
• The spark plug wires or ignition coil are damaged.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The fuel supply system is not functioning properly.
• The air cleaner filter element is blocked.
• The brakes are jammed.
• The ATF level in the AT has dropped.
• The oil pressure has dropped.
• The clutch is slipping (manual transmission).
• The fuel filter is clogged or moisture has entered the fuel system.
• The EGR system is not functioning properly.
• The vehicle is filled with non-standard fuel.
• The compression pressure has dropped or is unevenly distributed between the cylinders
• The patency of the exhaust tract is impaired.
• The fuel pump is faulty, or the pressure it produces has dropped.
• There are leaks in the air intake tract.
• The injection system or engine management system is not functioning properly.
• The engine is overheated.
• The engine has not warmed up to normal operating temperature.

"Shots" occur in the exhaust tract

• The EGR system is not functioning properly.
• The ignition timing angle setting is incorrect.
• The air purifier thermostat is not functioning properly.
• There are losses of vacuum.
• Valve clearance adjustment is incorrect.
• The valve springs are damaged or the valves are sticking.
• There are leaks in the air intake tract.
• There is a malfunction in the secondary (SH) circuit of the ignition system (spark plug insulators, high voltage wires, ignition module).
• The fuel supply system is not functioning properly.

The engine runs jerkily when the accelerator pedal is held motionless

• There are air leaks in the intake tract.
• The fuel pump is faulty.
• The fuel injector wiring connector has become loose.
• There are malfunctions in the engine management system.

During acceleration or when the engine load increases, knocking noises occur, caused by too early ignition or detonation

• The car was filled with the wrong type of fuel.
• The ignition timing angle setting is incorrect.
• There is excessive carbon formation in the combustion chambers.
• Non-standard spark plugs are installed.
• The fuel supply system is not functioning properly.
• The high voltage wires are damaged.
• The EGR valve is not functioning properly.
• There are losses of vacuum.
• The knock sensor is faulty.
• Valve clearance adjustment is incorrect.
• Valve springs are worn or damaged.
• There is a mechanical failure of the valve drive components (rocker arms, rocker arm axles, etc.).

The engine continues to run after the ignition is turned off (diesel effect)

• There are leaks in the injectors.
• Idle speed is set too high.
• The engine operating temperature is excessively high.
• The ignition timing angle setting is incorrect.
• There is excessive carbon formation on the piston crowns.
• The valves start to stick.
• The valve clearances are set incorrectly.
• The EGR system is not functioning properly.

There is a drop in engine oil pressure

• The oil level has dropped, or the wrong type of oil has been added.
• Engine bearings and/or oil pump are worn out.
• The engine is overheating.
• The oil filter is blocked.
• The oil intake mesh filter is clogged.
• Idle speed is set too low.
• A short circuit occurred in the on-board electrical wiring harness.
• The oil pressure gauge is faulty.

Excessive engine oil consumption

• The oil pan drain plug has come loose.
• The crankcase ventilation hose is damaged.
• The crankcase ventilation valve is faulty.
• The pan mounting bolts have become loose or its sealing gasket is damaged.
• The front cover mounting bolts are loose or its sealing gasket is damaged.
• The crankshaft oil seal is damaged.
• The cylinder head cover mounting bolts have become loose or its sealing gasket is damaged.
• The oil filter fit has become loose.
• The tightening force of the oil pressure switch sensor has weakened.
• There is excessive wear on the pistons or cylinders.
• Piston rings are worn or damaged.
• The intake and/or exhaust valve oil seals are worn or damaged.
• The valve stems are worn out.
• Valve guides are worn or damaged.

Various types of noise that occur during engine operation

• A loud, dull knock, which often occurs during acceleration, indicates wear or damage to the main bearings, or uneven wear of the crankshaft.
• A sound similar to that described above, but somewhat higher frequency, also occurring more often during acceleration, indicates possible wear of the connecting rod bearings.
• An overlapping metallic knock that intensifies with increasing engine speed and weakens as the engine warms up indicates excessive wear of the pistons and cylinder walls.
• Frequent clicking, which increases with acceleration, indicates wear of the piston pins or the seats under which they fit in the pistons (the sound occurs each time the corresponding piston passes TDC).
• A metallic clicking noise from the water pump indicates worn bearings and the need to replace the pump assembly.
• Frequent knocking or clicking noises that increase with increasing RPM may be due to valve clearances being out of adjustment - listen to the valve mechanism with a stethoscope/vacuum hose. If adjusting the valves does not correct the situation, check the hydraulic tappets and other valve mechanism components.

In some cases, filling the engine with oil with a higher viscosity coefficient helps eliminate knocking.

• A uniform metallic knocking or rattling noise from the timing belt on 3.0L models may be caused by timing chain wear or poor timing chain tension adjustment; also check the condition of the sprockets.

Diagnostics of lubrication system faults

Engine oil pressure warning light does not turn off

• The oil pressure sensor is damaged (the diaphragm is damaged, there is an oil leak, the spring is broken or the contacts are stuck).
• The oil pressure dropped as a result of a blockage in the full-flow oil filter.
• The oil pressure dropped as a result of a blockage in the oil pump pressure relief valve.
• The patency of oil flows is impaired.
• The oil intake mesh filter is clogged.
• The engine oil level has dropped.
• The oil intake is damaged.
• The oil pump rotors are jammed.

Oil pressure warning light does not come on when ignition is turned on

• The light bulb burned out.
• The electrical wiring is broken or the quality of the contact connections is compromised.

The control lamp starts to operate in a rapidly flashing mode

• The quality of the contact connections in the corresponding circuit is impaired.
• The oil pressure has dropped.
• The electrical wiring is damaged.

Diagnostics of faults in fuel supply and exhaust systems

There are problems with fuel supply to the injectors

• There is a fault in the electrical circuit of the fuel pump.
• Dust or moisture has entered the fuel pump.
• The fuel pump is clogged with dust or water.
• Air has entered the fuel system.
• The patency of the air or ventilation tract is impaired.
• The fuel pressure regulator is not functioning properly (for example, the diaphragm is damaged).

Excessive fuel consumption

• The air purifier filter element is dirty or its flow is otherwise impaired.
• Valve clearance adjustment is incorrect.
• The valve seats are worn out.
• The valve stems are damaged.
• Valve springs are worn or damaged.
• The ignition timing angle setting is incorrect.
• The spark plugs are worn or damaged, or the interelectrode gap setting is incorrect.
• The cylinder head cover mounting bolts have become loose or its sealing gasket is damaged.
• Piston rings are worn or burned.
• The valve timing is incorrect.
• Engine oil with excessively low viscosity is used.
• The idle speed setting is incorrect.
• There are leaks in the fuel line.
• The fuel injectors are not flowing properly.
• The fuel injection system or engine management system is not functioning properly.
• The toxicity reduction systems are not functioning properly.
• The tire inflation pressure is insufficient or the wrong size wheels are installed.
• the brakes are "stuck".
• The engine does not warm up to normal operating temperature.
• The throttle cable adjustment is out of adjustment.

There are fuel leaks (there is a distinct smell of gasoline in the car and around it)

• The fuel tank, fuel lines or their fittings are damaged mechanically or as a result of corrosion.
• The weld on the fuel tank has come apart.
• The fuel tank drainage system is damaged.
• The patency of ventilation lines is impaired.
• The tank is full.
• The EVAP system carbon canister is clogged.
• There are leaks in the EVAP system path.
• The fuel supply system is not functioning properly.
• Internal components of fuel injectors are damaged or excessively worn.

Fuel gauge gives incorrect readings

• The fuel level sensor assembly is damaged.

Noise

• The fuel pump is damaged.

The exhaust system is excessively noisy or smokes

• There are exhaust gas leaks through the joints of the exhaust manifold or sections of the exhaust system.
• The mufflers or exhaust pipes are damaged mechanically or as a result of corrosion.
• As a result of damage to the suspension supports, the exhaust system comes into contact with body or suspension elements during movement.

Diagnostics of cooling system faults

The engine gets very hot

• The coolant level has dropped.
• The timing belt is damaged or its tension adjustment is incorrect
• The accessory drive belt is contaminated with oil.
• The flow of water or air in the radiator is obstructed.
• There are coolant leaks from the radiator.
• The water pump is faulty.
• Thermostat is faulty.
• The coolant was filled with poor quality liquid.
• There is a fault in the cooling system fan circuit.
• There is mechanical damage to the impeller of the cooling system fan.
• The radiator cap is not tightly sealed.
• The ignition timing angle setting is incorrect.
• The air-fuel mixture is too lean.
• The clutch is slipping.
• the brakes are "stuck".
• Incorrect distance between the piston and the cylinder wall.
• The cooling system tract is blocked by an air lock.
• The transmission oil was filled with the wrong type.
• Exhaust tract resistance is too high (high back pressure).
• The temperature meter readings are inaccurate.

The engine does not warm up to normal operating temperature

• The ambient temperature is too low.
• Thermostat is faulty.
• There is a fault in the cooling system fan circuit.
• The temperature meter readings are inaccurate.

There are external coolant leaks

• The cooling system hoses are mechanically damaged or destroyed as a result of material aging, or their fastening clamps have become loose.
• Water pump seals are worn or damaged (coolant will leak through the inspection hole).
• There are coolant leaks from the radiator or expansion tank.
• The drain or release plugs of the engine block water jacket are damaged.
• The coolant temperature sensor switch is not sealed properly.
• The cylinder block/head gaskets are damaged or there are cracks in the casting.
• The thermostat housing is damaged.
• The radiator cap is faulty.
• The coolant boiled due to overheating.

There are internal coolant leaks

The presence of internal leaks is confirmed by the presence of coolant in the engine oil, causing emulsification of the latter.

• The cylinder head gasket is blown.
• The cylinder head or block is cracked.
• The cylinder head mounting bolts have come loose.

There is a loss of coolant

• There is too much coolant in the system.
• The coolant boils away as a result of overheating.
• There are external or internal coolant leaks (see above).
• The radiator cap is faulty.
• The pressure in the cooling system increases due to compression in the cylinders as a result of cracks in the head or block, or damage to the integrity of one of the sealing gaskets.

Coolant circulation is disrupted

• The water pump is faulty - check by feeling the upper radiator hose.
• The patency of the cooling tract is impaired.
• The water pump drive belt tension has weakened.
• Thermostat is stuck.
• The coolant level has dropped.

Various kinds of noise

• The drive belt is faulty.
• The cooling system fan is faulty.
• The water pump bearing is faulty.
• The water pump seal is damaged.

Corrosion development takes place

• The coolant is excessively contaminated - top up the system with distilled rainwater only.
• The antifreeze is overly diluted.
• The coolant is not replaced and the system is not flushed often enough.

Diagnostics of malfunctions of heating, ventilation and air conditioning systems

Heating and ventilation systems

The heater fan is completely out of order

• The corresponding fuse has blown.
• There was a break in the electrical wiring.
• There is an open circuit in the fan control switch/resistive assembly circuit.
• The fan drive electric motor is faulty.

The supply of heated air to the cabin is disrupted

• The fluid level in the engine cooling system is insufficient.
• The engine does not warm up to normal operating temperature (see above).
• The heater heat exchanger inlet valve is faulty. Check the correct operation of the cable/vacuum actuator of the valve. Move the temperature mode selection switch to the extreme positions several times, checking the correct operation of the valve. Warm up the engine to normal operating temperature and, having selected the maximum temperature mode of the heater, feel the hoses at the inlet and outlet of the valve assembly. If the hoses have different temperatures, replace the valve.

When the heater is turned on, the windshield fogs up

• There are coolant leaks from a hose located near the engine compartment bulkhead or under the vehicle's instrument panel - check that the mounting clamp is securely tightened.
• There are leaks of coolant from the heater heat exchanger. Carefully inspect the floor mats in the driver's and front passenger's footwells for leaks.

The coolant has a characteristic sweetish smell. If necessary, make the appropriate repairs or replace the failed heat exchanger.

On some models, to gain access to the heater heat exchanger (radiator), it is necessary to remove the instrument panel.

The temperature mode selection control is not functioning properly

• The coolant level has dropped.
• The electric motor driving the mode flap is faulty.

Unable to turn off closed ventilation mode

• The selector switch is faulty.
• There is a malfunction in the electric motor circuit of the corresponding damper.

Manual air conditioning system

In addition to the faults listed in the previous subsection:

Cold air does not flow through the ventilation deflectors

• The heater fan is faulty (see above).
• The heater fan control switch is faulty.
• The air ducts are obstructed.
• The air conditioning system needs charging.

Attention! Emptying, charging and checking the refrigeration system must be carried out in a specialized workshop!

• The accessory drive belt is broken or its tension has weakened.
• The K/V switch is faulty.
• The air conditioning compressor is faulty.
• The compressor clutch of the K/V compressor is not functioning properly. Check the condition of the clutch and its circuit wiring.
• Correct any identified faults and replace defective components.
• The low-pressure pressure switch sensor of the air conditioning system is faulty.
• There is damage to the wiring of the air conditioning system circuit, or the corresponding relay has failed. Check, eliminate the detected faults, replace the relay if necessary.

When using K/V, moisture streaks form on the floor in the cabin

• The evaporator drain tube of the air conditioning system is clogged. Clean the tube where it exits the car.
• The evaporator drain hose is clogged. Clean the hose where it exits the car.

Activation of the K/V is accompanied by the appearance of a moldy smell in the cabin

• The air conditioning system evaporator drain hose is clogged. Clean the hose where it exits the vehicle.

Automatic air conditioning system (climate control)

The system does not activate when the ignition is turned on

• Fuse #5 or #17 has blown.
• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired (special attention should be paid to the grounding circuit).
• The control assembly of the K/V is faulty.

The function to save the last selected mode does not work

• Fuse #5 or #17 has blown.
• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired (special attention should be paid to the grounding circuit).
• The control assembly of the K/V is faulty.

The display screen data output is not working properly

• Fuse #5 or #17 has blown.
• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired (special attention should be paid to the grounding circuit).
• The control assembly of the K/V is faulty.

Fan rotation stability is impaired

• Fuse #5 or #17 has blown.
• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired.
• The control assembly of the K/V is faulty.
• The fan motor is faulty.
• The fan motor relay is faulty.
• The power transistor or the corresponding fuse is faulty.

The functioning of the circulation mode on/off valve is impaired

• The quality of the contact connections in the corresponding electrical wiring is impaired.
• The control assembly of the K/V is faulty.
• The electric motor or potentiometer of the changeover flap drive is faulty.

The air distribution direction switching function does not work

• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired.
• The control assembly of the K/V is faulty.
• The electric motor or potentiometer of the selector flap drive is faulty.

The function of maintaining the set temperature in the cabin does not work

• The quality of the contact connections in the electrical wiring of the corresponding circuit is impaired.
• The control assembly of the K/V is faulty.
• The electric motor or potentiometer of the mixing flap drive is faulty.
• The K/V relay is faulty.
• The air conditioning compressor is faulty.
• The heater is faulty.
• The temperature and/or solar radiation intensity information sensors are faulty.

There is an excessive delay in transition to the selected temperature mode

• The electric motor or potentiometer of the mixing flap drive is faulty.
• The temperature and/or solar radiation intensity information sensors are faulty.

The functioning of the air conditioning fans is disrupted

• The main or auxiliary fan electric motor is faulty.
• The relay of the main or auxiliary fan electric motor is faulty.

Diagnosing Clutch Faults

The clutch release is faulty (when the pedal is pressed to the floor, it is difficult to engage/disengage reverse gear)

• The clutch pedal free travel adjustment is incorrect.
• Oil got onto the clutch driven disc.
• the diaphragm spring has sagged.
• There are hydraulic fluid leaks from the clutch master or slave cylinder.
• Air has entered the clutch hydraulic circuit (there is a soft pedal stroke).
• The sealing cuff of the piston of the master or slave cylinder is damaged.
• There is a lack of lubrication in the guide bearing.

The clutch is slipping (engine speed increases without increasing vehicle speed)

• The driven clutch disc is overheated - park the car and let the disc cool down.
• The friction linings of the driven disk are contaminated with oil leaking through the rear crankshaft oil seal.
• The new driven disk has not been run in (at least 30–40 starts are required for the new disk to be fully run in).
• There is deformation of the clutch basket/flywheel assembly.
• The diaphragm spring is weak.
• The piston in the clutch master cylinder became stuck due to foreign particles getting in.
• The clutch release mechanism is jammed.
• The pressure plate or flywheel is deformed.
• The clutch hydraulic lines are damaged.

Vibration occurs when the clutch is engaged

• The friction linings of the driven disk/working surface of the flywheel are contaminated with oil, deformed, burnt out, or polished to a shine.
• The rivets holding the friction linings have come loose.
• The powertrain suspension supports are worn out or their fastening has become loose.
• The splines of the gearbox input shaft or the driven disk hub are worn.
• There is deformation of the clutch basket/flywheel assembly.
• There is fatigue deformation of the diaphragm spring.
• The guide bearing in the crankshaft journal is jammed.

When pressing or releasing the clutch pedal, extraneous noises occur

• The clutch pedal adjustments are incorrect.
• The release bearing is jammed on the transmission shaft.
• The guide bearing is worn or damaged.
• The clutch slave disc is cracked.
• There is fatigue deformation of the torsion springs of the driven clutch disc.
• Clutch basket assembly components are worn out.
• The diaphragm spring of the pressure plate is broken.
• The clutch pedal axle bushings are worn out or dry.
• The clutch basket assembly is faulty.
• Engine idle speed is too low.

The clutch pedal does not return to its original position after being released

• The master or slave cylinder of the clutch is not functioning properly.
• The piston in the master or slave cylinder is jammed.
• Clutch release drive components are damaged or jammed.
• Air has entered the hydraulic system.

Excessive force is required to depress the clutch pedal

• The piston in the master or slave cylinder is jammed.
• The clutch basket assembly is faulty.
• The master or slave cylinder is the wrong size.

Manual Transmission Fault Diagnosis

The gearbox is set to neutral and makes noise when the engine is running

• The primary shaft bearings are worn out (noise appears when releasing the clutch pedal and disappears when depressing it).
• The bearing of the input shaft of the gearbox is worn out.
• The transmission oil level has dropped.
• The clutch release bearing is worn out (noises appear when the clutch pedal is depressed and may decrease when it is released).
• The source of the noise may be variations in engine torque - adjusting the idle speed may correct the situation.

Noises occur in all gears

Any of the above reasons, and/or:

• The secondary shaft of the gearbox or its bearings are worn or damaged.

Noises occur in a particular gear

• The transmission gear teeth are worn, chipped or otherwise damaged.
• Synchronizers are worn or damaged.

Noise occurs when shifting gears

• The clutch is not functioning properly.
• Synchronizer assemblies are faulty.

The gearbox "jumps" out of the selected gear

• The gear shift lever cuff has hardened.
• The gear shift drive components are jammed.
• The gear shift mechanism is worn out.
• The bolts securing the manual transmission to the engine have come loose
• The primary gear bearing holder is broken or its fastening is loose.
• Dirt got between the clutch lever and the engine crankcase.
• The control balls, the grooves of the spherical bearings of the shift fork rods, or the control springs are worn or damaged.
• The driven or intermediate shaft bearings are worn out.
• The powertrain suspension mounts are worn out.
• Excessive axial clearance of gears.
• The synchronizers are worn out.

There are transmission oil leaks

• There is too much transmission oil in the gearbox.
• The differential seal or speedometer seal is damaged.

Difficulty shifting gears

• Clutch faulty.
• The gear shift drive components are worn or damaged.
• The transmission oil level has dropped.
• The transmission oil needs to be changed.
• The impact rod is worn or damaged.
• The manual transmission gears are jammed.
• The synchronizer blocks are worn out.

The gearbox is locked in one of the gears

• There is wear or loosening of the drive rod.

Automatic Transmission Fault Diagnosis

Due to the complexity of the AT design, it will be difficult for the average amateur mechanic to accurately diagnose its failures and perform repairs. In the event of problems other than those listed below, the car owner should seek help from car service specialists. You should also not rush to dismantle the faulty transmission, since many of its checks are performed in situ (in its regular place).

ATF leaks

• ATF is usually dark red in color - its leaks should not be confused with those of engine oil (the latter can be blown onto the transmission housing by the oncoming air flow).
• To identify the source of the leak, first of all, clean the transmission housing and surrounding surfaces from dirt and grease. Use a high-quality degreaser or steam clean the unit. Take the car for a short drive at low speed (so that traces of an existing leak are not carried far from its source). Jack up the car and place it on supports. Inspect the transmission case, visually identifying sources of ATF leakage. The most common sources are:
• Transmission Oil Pan: Tighten Fasteners and/or Replace Gasket;
• Rear Transmission Extension: Tighten Fasteners and/or Replace Seal;
• Filler neck: replace the rubber seal where the filler neck enters the transmission housing;
• Breather tube: transmission is overfilled and/or water has entered the crankcase;
• Speedometer connection unit: Replace the O-ring where the drive cable enters the transmission case.

ATF is brown in color or smells burnt

• The ATF level in the transmission has dropped, or the fluid has burnt and needs to be replaced.
• The overdrive clutch is faulty.
• The 2/4 gear brake band is faulty.
• The clutch of the lower and reverse gears is faulty.
• The reverse clutch is faulty.

The transmission does not automatically downshift when the gas pedal is fully depressed (kickdown mode)

• The throttle cable adjustment is incorrect when kickdown mode is engaged.

The engine stalls when shifting gears

• The control valve is faulty.
• The locking damper is faulty.
• Engine settings are out of adjustment.
• The transmission input shaft is faulty.

The engine starts in a transmission position other than "P" or "N"

• The start enable switch sensor is faulty or its adjustment is incorrect.
• The gear selector lever or gear selector actuator is faulty.

Unusual noise occurs when the selector lever is in the "P" or "N" positions

• The mesh filter is clogged.
• The oil pump is faulty.
• The drive disk is faulty.
• ATF level too high or too low.

Noises occur in the "D" position of the selector lever

• The final drive is faulty.
• The planetary assembly is faulty.
• The brake band of the lower and reverse gears is faulty.
• The reduction gear is faulty.
• The differential oil level is too high or too low.

The vehicle is moving in the "N" position of the selector lever

• The transmission control module (TCM) is faulty.
• The low gear clutch is faulty.

Shifting from "N" to "D" or "R" is accompanied by a jolt

• The transmission control module (TCM) is faulty.
• The electrical wiring is faulty.
• The control valve is faulty.
• ATF needs to be replaced.

Switching from "N" to "D" or "R" occurs with a delay

• The control valve is faulty.
• Line pressure solenoid valve malfunction.
• The sealing ring is worn out.
• The front crankcase gasket of the AT is damaged.
• The clutch of the lower and reverse gears is faulty.
• The reverse clutch is faulty.

The car does not move in any AT position (the engine stalls)

• The parking brake is set.
• The planetary assembly is faulty.

The car does not move in any AT position (the engine increases its speed)

• The mesh filter is clogged.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The drive gear is faulty.
• The hypoid gear is faulty.
• The drive shaft is damaged.
• The differential is faulty.
• The oil pump is faulty.
• The input shaft is faulty.
• The output shaft is faulty.
• The planetary gear is faulty.
• The drive disk is faulty.
• ATF level too low.
• The front gasket of the AT housing is damaged.

The car does not move only in the "R" position of the AT (the engine stalls)

• The parking brake is set.
• The low gear clutch is faulty.
• The 2/4 gear brake band is faulty.
• The planetary gear is faulty.

The car does not move only in the "R" position of the AT (the engine increases its speed)

• The selector cable is faulty.
• The selector lever is faulty.
• The control valve is faulty.
• The clutch of the lower and reverse gears is faulty.
• The reverse clutch is faulty.

The car does not move only in positions "D" and "3" AT (the engine increases its speed)

• The low gear clutch is faulty.
• The overrunning clutch is faulty.

The car does not move only in positions "D", "3" and "2" AT (the engine stalls)

• The reverse clutch is faulty.

The car does not move only in positions "D", "3" and "2" AT (the engine increases its speed)

• The low gear clutch is faulty.

The engine starts only in the "R" position of the selector

• The control valve is faulty.

Poor reception when accelerating from a standstill

• The control valve is faulty.
• The low gear clutch is faulty.
• The reverse clutch is faulty.
• ATF level too high or low.
• The oil pump is faulty.
• The front gasket of the AT housing is damaged.
• The torque converter lockup clutch is faulty.
• Differential oil level too high or too low.

Weak acceleration when accelerating from a standstill

• The transmission control module (TCM) is faulty.
• The control valve is faulty.
• The overdrive clutch is faulty.
• The planetary gear is faulty.
• The 2/4 gear brake band is faulty.

The transmission does not shift from 1st to 2nd gear

• The transmission control module (TCM) is faulty.
• The throttle position sensor is faulty.
• Shift solenoid valve 1 is faulty.
• The gas pedal position sensor is faulty.
• The 2/4 gear brake band is faulty.
• The control valve is faulty.

There is no shifting from 2nd to 3rd gear

• The transmission control module (TCM) is faulty.
• The control valve is faulty.
• The overdrive clutch is faulty.
• Shift solenoid valve 2 is faulty.

There is no shifting from 3rd to 4th gear

• The transmission control module (TCM) is faulty.
• Shift solenoid valve 1 is faulty.
• The ATF temperature sensor is faulty.
• The control valve is faulty.
• The 2/4 gear brake band is faulty.

Reduced engine braking efficiency in selector lever position "3"

• The start enable/selector lever position switch sensor is faulty.
• The transmission control module (TCM) is faulty.
• The control valve is faulty.
• The throttle position sensor (TPS) is faulty.

Reduced engine braking efficiency in selector lever positions "3" or "2"

• The control valve is faulty.

Reduced engine braking efficiency in selector lever position "1"

• The clutch of the lower and reverse gears is faulty.

The transmission shift pattern is disrupted

• The start enable/selector lever position switch sensor is faulty.
• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The control valve is faulty.
• The quality of grounding is impaired.

Transmission lock does not occur

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The control valve is faulty.
• The engine speed signal output is faulty.

The parking brake does not securely hold the vehicle/the selector lever is difficult to move out of the "P" position

• The selector cable is faulty.
• The selector lever is faulty.
• The parking brake mechanism is faulty.

Shifting from 1st to 2nd gear is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The 2/4 gear brake band is faulty.
• ATF needs to be replaced.
• Engine settings are out of adjustment.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.

Shifting from 1st to 2nd gear is accompanied by transmission slippage

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The check valve is faulty.
• The 2/4 gear brake band is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.
• The overdrive clutch is faulty.

Shifting from 2nd to 3rd gear is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The overdrive clutch is faulty.
• The 2/4 gear brake band is faulty.
• ATF needs to be replaced.
• Engine settings are out of adjustment.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.

Shifting from 2nd to 3rd gear is accompanied by transmission slippage

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The overdrive clutch is faulty.
• The 2/4 gear brake band is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.

Shifting from 3rd to 4th gear is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.
• The 2/4 gear brake band is faulty.
• ATF needs to be replaced.
• Engine settings are out of adjustment.
• The synchronizing electromagnetic valve of the low gear clutch electromagnetic valve is faulty.
• The low gear clutch is faulty.

Shifting from 3rd to 4th gear is accompanied by transmission slippage

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The 2/4 shift solenoid valve is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The 2/4 gear brake band is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.

Moving the selector lever from position "3" to position "2" is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The 2/4 shift solenoid valve is faulty.
• The 2/4 gear brake band is faulty.
• ATF needs to be replaced.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.

The shift of the selector lever from position "D" to position "1" is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• ATF needs to be replaced.
• The 2/4 shift solenoid valve is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.
• The synchronizing electromagnetic valve of the low gear clutch is faulty.

Moving the selector lever from position "2" to position "1" is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The clutch of the lower and reverse gears is faulty.
• ATF needs to be replaced.
• The 2/4 shift solenoid valve is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.
• The synchronizing electromagnetic valve of the low gear clutch is faulty.

Releasing the gas pedal at medium speeds is accompanied by jolts

• The transmission control module (TCM) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The functioning of the linear pressure solenoid valve is impaired.
• The control valve is faulty.
• The locking damper is faulty.
• Engine settings are out of adjustment.
• The 2/4 shift solenoid valve is faulty.
• The 2/4 gear brake synchronizing electromagnetic valve is faulty.
• The synchronizing electromagnetic valve of the low gear clutch is faulty.

Rectilinear movement is accompanied by an increased level of vibrations

• The transmission control module (TCM) is faulty.
• The electromagnetic valve for engaging the lock is faulty.
• The locking damper is faulty.

Vibrations occur when turning

• The transmission control module (TCM) is faulty.
• The front vehicle speed sensor (VSS) is faulty.
• The rear vehicle speed sensor (VSS) is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• ATF needs to be replaced.
• The transfer case clutch is faulty.
• The transfer case valve is faulty.

When the car starts moving, the front wheels begin to slip

• The transmission control module (TCM) is faulty.
• Front VSS is faulty.
• The all-wheel drive (FWD) activation switch sensor is faulty.
• The throttle position sensor (TPS) is faulty.
• The ATF temperature sensor is faulty.
• The control valve is faulty.
• ATF needs to be replaced.
• The transfer case clutch is faulty.
• The valve of the distribution mechanism is faulty.
• The patency of the dispensing mechanism tube is impaired.

The vehicle does not switch to all-wheel drive (FWD) mode

• The transmission control module (TCM) is faulty.
• The all-wheel drive (FWD) activation switch sensor is faulty.
• The transfer case clutch is faulty.
• The valve of the distribution mechanism is faulty.

The transmission "jumps" from the selected position, shifts with difficulty or noise, or does not provide forward or backward movement of the car

• There are many possible causes for the listed failures, but only one of them falls within the competence of the average amateur mechanic - a violation of the ATF level. Check, if necessary, adjust the level / replace the fluid and filter, and simultaneously check the condition of the ATF. In all other cases, the car should be driven to a service station for diagnostics and restoration repair / replacement of the transmission.

Diagnosis of faults of the cardan shaft

There are leaks in the front part of the propeller shaft

• The rear transmission seal is damaged or worn. Also check the condition of the sliding clamp surface.

When the gear is engaged (at the moment the load appears) a knocking sound occurs

• The rear suspension components have become loose.
• The sliding clamp spindle is worn out.
• The driveshaft bolts/nuts have become loose.
• The universal joint bearings are worn or damaged.
• The center bearing/center support cushion is worn out.

There is a metallic grinding sound, corresponding to the speed of the vehicle

• The universal joint bearings are worn out.

Vibrations occur

First of all, check the wheel balance and tire inflation pressure. Usually, vibrations increase with increasing movement.

• Install a tachometer in the car and while driving, try to determine the engine speed at which the vibration reaches its maximum intensity, then change gears and bring the engine speed to the same value.
• If vibration occurs and reaches maximum intensity at the same engine speed, regardless of the selected gear, its source is not the cardan shaft, since its rotation frequency depends on the choice of gear ratio.
• If shifting the gear results in the disappearance of vibration or a noticeable reduction in its intensity (at the same engine speed), you should proceed to check the condition of the cardan shaft:
• Check the driveshaft for signs of bending and other deformations, replace if necessary;
• Clean the shaft thoroughly - stuck dirt can cause imbalance;
• Assess the degree of wear of the universal joint bearings and replace the assemblies if necessary;
• Check the balance of the cardan shaft or its connecting flange. Make sure that the balancing weights are in place, remove the shaft and install it by turning it 180° - if the vibrations do not disappear, send the shaft for balancing;
• Check that the mounting bolts/nuts are securely tightened;
• Assess the degree of wear of the central bearing;
• Check the condition of the rear transmission bushings.

There is a scraping sound

• Make sure the sliding clamp dust cover does not rub against the rear transmission extension housing.

There is a howling or whistling sound

• The source of such sounds may be the central bearing.

Diagnostics of faults of the rear axle and main gear

There is extraneous noise, the same when moving in gear and coasting

• Natural road noise.
• Excessive differential play.
• Excessive backlash of hypoid gear.
• The pinion nut is loose or missing.
• The tires are worn out or improperly inflated.
• Wheel bearings are worn, damaged or loose.
• The oil level in the differential has dropped.
• The differential is faulty.

There is a knocking noise that occurs when starting off or when changing gears

• The differential is faulty or its adjustment is incorrect.

Extraneous sounds occur when turning

• The differential is faulty.
• The thrust washer is excessively worn.
• The slip clutch is stuck or damaged.

There are oil leaks

• The breather is clogged or damaged.
• The differential axle or side carrier bolts are loose or missing, or the O-ring is not installed correctly.
• The rear cover bolts are loose, missing, or the gasket is damaged.
• The oil filter is broken, or the drain plug is loose (lost).

Vibrations occur

• See the section on diagnosing driveshaft faults. If the shaft is OK, jack up the rear of the car and place it on supports, manually assess the condition of the wheel bearings, and replace them if necessary.

There are oil leaks

• The seal of the main gear drive pinion is damaged.
• The axle shaft seals are damaged.
• The fastener is loose or the differential cover sealing gasket is damaged.
• The differential drain or fill/inspection plug is loose.
• The differential breather patency is impaired.

Transfer case fault diagnostics (with the appropriate vehicle configuration)

The gears are jumping out of engagement

• The amount of free play of the control lever is violated.
• The control lever is hooked onto the console.
• The fastening of the transfer case suspension supports has become loose, or there is fatigue deformation of the material.
• The internal components of the transfer case are worn out or the adjustments are out of order.

Difficulty switching modes

• The oil level has dropped.
• The internal components of the transfer case are worn out or the adjustments are out of order.

There are extraneous noises

• The oil level in the transfer case has dropped.
• The presence of noise when selecting any of the modes indicates a malfunction in the components of the rear differential or rear axle.

Diagnostics of brake system faults

Before concluding that the brake system is failing, check the condition and inflation pressure of the tires, the uniformity of the vehicle loading, and the alignment angles of the front wheels.

When braking, the vehicle's directional stability is impaired

• The tires are not inflated correctly.
• The front wheel alignment angles are out of adjustment.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The brake pads/shoes on one side of the vehicle are worn, damaged or oily.
• The brake pads or disc on one side of the vehicle are excessively worn.
• The fastening of the front suspension components has become loose.
• One or more brake mechanisms are faulty.
• The patency of the brake lines is impaired.
• The brake caliper or shield mounting bolts have become loose.
• The piston of the caliper/wheel cylinder of one of the brake mechanisms is jammed, or its movement is difficult.
• Brake pads/shoes with different types of friction linings are installed on different sides of the vehicle.
• Steering or suspension components are worn or damaged.
• Wheel bearing preload adjustment is incorrect.

Extraneous noises occur during braking (grinding or high-pitched squealing noise)

• The friction linings of the front brake pads are worn out - the sound is emitted by the pad wear sensors.
• The brake pads are dirty or polished to a shine.
• Oil has gotten onto the working surface of the brake pad (clicks are heard).
• The brake disc/drum is damaged by corrosion - usually after the car has been parked for a long time.
• A foreign object has gotten between the disc and the brake shield (for example, a stone).
• The brake shield is deformed.

Brake pedal travel is too long

• There is a local fault in the braking system.
• The hydraulic fluid level in the master cylinder reservoir has dropped.
• Air has entered the hydraulic system.
• The automatic brake regulators are not functioning properly.
• The limiting valve is faulty.
• The master cylinder is faulty.
• The brake booster is faulty.

There is a softness in the brake pedal when it is pressed

• Air has entered the hydraulic system.
• Flexible brake hoses are damaged as a result of material aging.
• The brake master cylinder fastener has become loose.
• The master cylinder is faulty.
• The working clearances of the brake pads/shoes are not set correctly.
• The patency of the ventilation hole of the master cylinder reservoir cover is impaired.
• The rubber brake lines are deformed.
• The caliper seals have softened.
• The brake fluid needs to be replaced.

To stop the car, it requires applying excessive force to the brake pedal

In addition to the reasons listed in the previous subsection:

• The brake booster is faulty.
• The friction linings of the brake pads/shoes are excessively worn.
• The caliper/wheel cylinder piston is stuck.
• The friction linings of the brake pads/shoes are contaminated with oil or grease.
• The brake discs are damaged or worn out.
• The brake master cylinder or caliper/wheel cylinder is faulty.
• New brake pads/shoes have been recently installed and have not had time to break in.
• There is a local fault in the braking system.

The foot brake pedal sinks to the floor without resistance

• The fluid level in the brake master cylinder reservoir has dropped, or there are leaks through the caliper/wheel cylinder pistons.
• The brake lines are damaged or their fittings are loose.

Pulsations in the foot brake pedal occur during braking

• Wheel bearings are worn or damaged, or their preload adjustment is incorrect.
• The brake caliper components are not installed correctly, or foreign objects have gotten between them.
• There is excessive lateral runout of the brake disc/drum out of roundness.
• The brake pads are worn unevenly.

There is pulsation of the foot brake pedal when it is depressed during sudden braking

• Consequence of proper functioning of ABS.

When braking, vibration occurs that is transmitted to the brake pedal or steering wheel

• There is excessive runout of the brake disc/deformation of the brake drum.
• The friction linings of the brake pads/shoes are worn out.
• The caliper/brake shield mounting bolts have come loose.
• Suspension or steering components or supports are worn.

The brakes are "stuck" (reduced engine efficiency, wheels overheat while driving)

• The adjustment of the foot brake pedal output rod is disturbed.
• The flow of the master cylinder inlet fitting is obstructed.
• The master cylinder piston is jammed in the cylinder.
• Brake pads/shoes are excessively worn.
• The piston cups in the main brake cylinder or brake calipers are deformed.
• The parking brake adjustment is incorrect.
• Wheel bearing preload adjustment is incorrect.
• The foot brake pedal installation height adjustment is incorrect.
• The wheel cylinder is jammed.
• The clearance adjustment of the shoes in the brake drums is incorrect.
• The master cylinder is faulty.
• The patency of the brake lines is impaired.

The rear wheels lock up under normal braking

• The tires are over-inflated.
• The treads are excessively worn.

The rear wheels lock during emergency braking

• The tires are over-inflated.
• The treads are excessively worn.
• The brake pads on the front wheels are contaminated with oil.
• The brake master cylinder or brake assembly is faulty.

the parking brake is "stuck"

• The parking brake lever is not adjusted.
• The parking brake cable does not move.
• The parking brake shoe clearance is not adjusted.
• The return spring is broken.

Noise from the parking brake mechanism

• The return spring is broken.
• The parking brake shoe retaining spring is broken.

The parking brake does not hold the vehicle properly

• The parking brake drive adjustment is incorrect.

Diagnostics of malfunctions of the anti-roll device

Attention! If the car does not move (the brake does not release) due to broken return spring, loosen the adjusting nut, disconnect the clutch and pressure holding valve (PHV), then release the brakes by returning the PHV lever to its original position.

Before you begin this operation, make sure the parking brake is engaged.

The anti-roll device does not function on gentle inclines.

The clutch pedal is depressed with excessive resistance

• The pressure holding valve (PHV) drive cable is faulty.
• The PHV lever is faulty.
• Clutch faulty.

The vehicle does not remain stationary on an incline of more than 3%

• The front of the car body is lowered excessively.
• The PHV drive cable is broken or stretched.
• The clutch pedal free play is excessive.
• PHV seal is broken (the valve must be replaced as an assembly).

The car starts moving with a jolt

• The foot brake pedal is pressed too hard (the harder the pedal is pressed, the later the anti-roll device is released).
• When starting off on a level surface, the car may initially jerk backwards - the result of activation of the anti-roll device.

The car slips when starting

• The clutch disc is worn out.
• The pressure holding valve (PHV) cable is pulled out.
• The cable assembly support bracket or PHV valve stand is deformed.

The car cannot start moving when starting

• The return spring is stretched or broken.
• The pressure holding valve (PHV) lever does not return to its original position.

An unusual sound occurs when releasing the foot brake pedal

• The brake pads are pressed excessively hard against the brake disc as a result of sudden braking.

When pressing the clutch pedal, an unusual sound occurs

• The return spring hook or the moving section of the PHV drive cable tip is not sufficiently lubricated.
• Clutch faulty.

Diagnosing faults in the anti-lock brake system (ABS)

Loss of directional stability when braking (the car pulls to one side or turns around)

• The solenoid valve of the hydraulic modulator/ABS control unit is faulty.
• The ABS sensor is faulty.
• The brake mechanisms/pads are faulty.
• The hydraulic lines/electrical wiring are not connected correctly.
• The front wheel alignment angles are out of adjustment.
• On one axle of the car (front or back) wheels of different sizes are installed.
• Wrong (unevenly) the tires are inflated.
• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• Uneven road.

Braking distance is excessive

• The solenoid valve of the hydraulic modulator/ABS control unit is faulty.
• The ABS sensor is faulty.
• Air got into the brake system.
• On one axle of the car (front or back) wheels of different sizes are installed.
• Wrong (unevenly) the tires are inflated.

Premature wheel locking occurs

• The solenoid valve of the hydraulic modulator/ABS control unit is faulty.
• The ABS sensor is faulty.
• The brake mechanisms/pads are faulty.
• The hydraulic lines/electrical wiring are not connected correctly.

The brakes are "stuck"

• The ABS hydraulic modulator/control module solenoid valve is faulty.
• The ABS sensor is faulty.
• The brake master cylinder (MBC) is faulty.
• The brake mechanisms are faulty (for example, the piston is jammed).
• The hydraulic lines/electrical wiring are not connected correctly.
• The parking brake adjustment is incorrect.
• The foot brake pedal travel adjustment is incorrect.
• Wheel alignment is out of adjustment.
• On one axle of the car (front or back) wheels of different sizes are installed.

The foot brake pedal travel is too long

• The corresponding adjustment is violated.
• Air got into the brake system.
• The hydraulic lines/electrical wiring are not connected correctly.

When braking, the car's nose dives excessively

• The ABS hydraulic modulator/control module solenoid valve is faulty.
• The ABS sensor is faulty.
• Suspension components are worn, damaged or loose.
• The brake mechanisms/pads are faulty.
• The hydraulic lines/electrical wiring are not connected correctly.
• Wheel alignment is out of adjustment.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The tires are not inflated correctly.
• Uneven road.

Vibration of the foot brake pedal when braking on a slippery road

• Normal sign of ABS activation (when braking).
• Uneven road surface.

The operation of the ABS hydraulic modulator is accompanied by extraneous noises

• The hydraulic modulator support bushing is faulty.
• The ABS sensor is faulty.
• The brake lines are damaged.

When driving on slippery surfaces, noise occurs in the front of the car

• The ABS hydraulic modulator support bushing is faulty.
• The ABS sensor is faulty.
• The master cylinder is faulty.
• The brake mechanisms/pads are faulty.
• The hydraulic lines of the brake system are faulty.
• Brake booster/check valve is faulty.
• Suspension components are worn, damaged or loose.

When driving on slippery surfaces, noise occurs in the rear of the car

• The ABS sensor is faulty.
• The brake mechanisms/pads are faulty.
• The parking brake is faulty.
• The hydraulic lines of the brake system are faulty.
• Suspension components are worn, damaged or loose.

Vehicle Dynamic Control (VDC)/Traction Control System (TCS) Malfunction Diagnosis

Braking distance is excessive

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• The brake mechanisms/pads are faulty.
• Air got into the brake system.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The tires are not inflated correctly.
• Brake lines/wiring not connected correctly.
• The ABS sensor is faulty or its operating gap is set incorrectly.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The yaw rate/lateral load sensor is faulty.
• The pressure limiting valve is faulty.
• The master cylinder is faulty.
• The brake booster is faulty.
• The hydraulic lines of the brake system are faulty.

Premature wheel locking occurs

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• The ABS sensor is faulty.
• The brake mechanisms/pads are faulty.
• The hydraulic lines/electrical wiring are not connected correctly.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The pressure limiting valve is faulty.
• The hydraulic lines of the brake system are faulty.

The brakes are "stuck"

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• The ABS sensor is faulty.
• The master cylinder is faulty.
• The parking brake failed.
• The foot brake pedal travel is not adjusted.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The brake mechanisms/pads are faulty.
• The hydraulic lines of the brake system are faulty.

The foot brake pedal travel is too long

• The corresponding adjustment is violated.
• Air got into the brake system.
• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The pressure limiting valve is faulty.
• The master cylinder is faulty.
• The brake mechanisms/pads are faulty.
• The hydraulic lines of the brake system are faulty.
• The brake booster is faulty.

When braking, the car's nose dives excessively

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• ABS sensor is faulty
• The brake mechanisms/pads are faulty.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The tires are not inflated correctly.
• The hydraulic lines/electrical wiring of the brake system are not connected correctly.
• Uneven road.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The master cylinder is faulty
• The hydraulic lines of the brake system are faulty.
• Suspension components are worn, damaged or loose.

Excessive vibration of the foot brake pedal Vibrations occur when braking, accelerating sharply or driving on a slippery road

• Uneven road.
• The hydraulic lines/electrical wiring of the brake system are not connected correctly.
• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The pressure limiting valve is faulty.
• The brake booster is faulty.

The operation of the VDC hydraulic modulator is accompanied by extraneous noises

• The hydraulic modulator support bushing is worn out.
• The hydraulic modulator is faulty.
• The ABS sensor is faulty.
• The yaw rate/lateral G sensor is faulty or incorrectly installed.
• The hydraulic lines of the brake system are faulty.
• The steering angle sensor is faulty or its neutral position is not set correctly.

Noises occur in the front of the vehicle when braking sharply, accelerating and driving on slippery roads

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The ABS sensor is faulty.
• The master cylinder has failed.
• The brake mechanisms/pads are faulty.
• The hydraulic lines of the brake system are faulty.
• The brake booster has failed.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The tires are not inflated correctly.

Noises occur in the car's interior

• Vehicle Dynamic Control (VDC) module is faulty;
• The steering angle sensor is faulty or its neutral position is not set correctly.

Noises occur in the front of the vehicle when braking sharply, accelerating and driving on slippery roads

• The ABS sensor is faulty.
• The brake mechanisms/pads are faulty.
• The parking brake is faulty.
• Suspension components are excessively worn, damaged or loose.
• The axle shafts are damaged.
• The wheels are damaged.
• Non-standard tires are installed.

The engine does not accelerate or stalls during sudden acceleration or when driving on a slippery road

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• ABS sensor is faulty
• The master cylinder is faulty.
• The parking brake failed.
• The hydraulic lines/electrical wiring of the brake system are not connected correctly.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The brake mechanisms/pads are faulty.
• The hydraulic lines of the brake system are faulty.

The dynamic stabilization system is activated under normal driving conditions

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.
• The ABS sensor is faulty.
• The steering angle sensor is faulty or its neutral position is not set correctly.
• The brakes are faulty (brake pads).
• The brake mechanisms/pads are faulty.
• Wheel alignment is out of adjustment.
• On one axle of the car (front or back) wheels of different sizes are installed.
• The tires are not inflated correctly.
• Uneven road.
• Malfunctions in the power steering system (PS).
• The hydraulic lines/electrical wiring of the brake system are not connected correctly.

VDC off indicator light does not light when "VDC OFF" switch is pressed

If the "VDC OFF" switch is pressed for 10 seconds or more while the engine is running, the VDC off indicator will go out permanently. To return to the working position, turn the ignition off and back on.

• The hydraulic modulator of the dynamic stabilization system (VDC) is faulty.
• The VDC control module is faulty.

Diagnosis of suspension and steering faults

Before you begin checking suspension and steering components, make sure that the problem is not caused by improper tire inflation, different tire sizes, unbalanced wheels, or dragging brakes.

The vehicle's directional stability is impaired

• Wheels of different sizes are mounted on one axle, or their tires are inflated to different pressures.
• There is a defect in the tires.
• Suspension or steering components are worn out.
• The front wheel alignment angles are out of adjustment.
• the front wheel brakes are "seized".
• Wheel bearing preload adjustment is incorrect.
• Broken or sagging coil springs (with the appropriate vehicle configuration).
• The wheel nuts have come loose.
• The suspension or steering geometry has been compromised as a result of an accident.

There is play in the wheels and increased vibration of the vehicle

• The front wheels are out of balance (vibration is most noticeable through the steering wheel).
• The rear wheels are out of balance (vibration is most noticeably transmitted through the car body).
• The tires are not inflated equally.
• Wheel bearing preload adjustment is incorrect.
• Suspension strut components are worn out.
• The wheel nuts have come loose.
• Wheel rims are damaged or deformed.
• The tires are damaged.
• The steering or suspension components, or their ball joints and/or rubber-to-metal bushings, are worn out.
• The ball joint is worn out.

During cornering and braking, the vehicle "gallops" and / or sways

• The anti-roll bar mount has become loose.
• The shock absorbers are faulty.
• The coil springs/suspenders are broken or "sagged".
• The steering or suspension components, or their ball joints and/or rubber-to-metal bushings, are worn out.
• The car is overloaded.

There is yawing or general directional instability of the vehicle

• Wheels of different sizes are mounted on one axle, or their tires are inflated to different pressures.
• The wheels are out of balance.
• The tires are unevenly inflated.
• The wheel nuts have come loose.
• There is a lack of lubrication of the CV joints and steering rod ends.
• The shock absorbers are worn out.
• The anti-roll bar mount has become loose.
• The coil springs/leaf springs are broken or have sagged.
• The front wheel alignment angles are out of adjustment.
• The steering or suspension components, or their ball joints and/or rubber-to-metal bushings, are worn out.

The steering wheel is too hard to turn

• The power steering fluid level has dropped.
• The tires are not inflated correctly.
• There is a lack of lubrication of the ball joints and steering rod ends.
• The front wheel alignment angles are out of adjustment.
• The steering gear adjustment is out of order or the lubrication level has dropped.
• Wheel bearing preload adjustment is incorrect.
• Steering gear components are worn or damaged.
• The turn signal switch interferes with the rotation of the steering shaft.
• The tires are too underinflated.
• The lubricant has deteriorated. Replace it.
• Ball joints are worn or damaged.
• Steering components are worn or damaged.

Excessive play in the steering wheel

• The wheel bearings have become loose.
• The bushings of the suspension components are worn out.
• The steering gear adjustment is out of adjustment.
• The front wheel alignment angles are out of adjustment.
• The steering gear assembly fasteners have become loose.
• Steering or suspension components are worn.

No hydraulic boost

• The steering pump drive belt is damaged or its tension adjustment is incorrect.
• The hydraulic fluid level has dropped.
• The patency of the power steering system hoses is impaired.
• Air has entered the hydraulic circuit of the power steering system.
• The steering pump is faulty.
• The steering mechanism is faulty.

The steering wheel return function to the straight-ahead position is faulty

• The front wheel alignment angles are out of adjustment.
• The tires are too underinflated.
• Steering gear components are worn out.
• The steering column adjustment is out of adjustment.
• Ball joints are worn or damaged.
• Steering components are worn or damaged.
• There has been a loss of lubrication of the steering gear components.
• The lubrication level in the steering gear housing has dropped.
• The steering column is jammed.

The steering wheel rotates in different directions with different resistance

• There are leaks in the steering gear housing.
• The hydraulic lines of the power steering system are not clear.

The operation of the steering pump is accompanied by increased background noise

• There is a lack of oil in the pump.
• The patency of the hoses or the oil filter of the steering pump is impaired.
• The drive pulley fastener has become loose.
• The steering pump drive belt tension adjustment is incorrect.
• The steering pump is faulty.

There are extraneous noises coming from the front of the car

• The tires are not inflated correctly.
• There has been a loss of lubrication of the ball joints or steering components.
• The fastening of the steering gear, steering drive components and suspension is loose.
• The shock absorber mounts are worn out.
• The shock absorbers are damaged.
• The springs are damaged.
• The wheel nuts have come loose.
• The splines of the rear axle shafts are worn or damaged.
• Excessive rear axle play.

During braking, the vehicle's controllability decreases

• The front wheel bearings are worn out.
• The coil springs/suspenders are broken or "sagged".
• There is deformation of the brake discs/drums.

The car sank excessively

• Overload.
• The shock absorbers of the strut assemblies are worn out.
• The coil springs/suspenders are broken or "sagged".
• The functioning of the electropneumatic suspension is impaired (with appropriate equipment).

There is grinding or other extraneous noise coming from the steering mechanism

• The rack and pinion assembly fasteners have become loose.
• There is internal damage to the steering mechanism.

There is excessive wear on the tires

Increased wear on the inner or outer part of the tread

• Tires are underinflated (wear on both edges).
• The front wheel alignment angles are out of adjustment.
• The steering or suspension components, or their ball joints and/or rubber-to-metal bushings, are worn out.
• No reduction in speed on turns.
• There is a mechanical violation of the suspension geometry as a result of an accident.

Flaky wear (fraying) protector

• The convergence setting is broken.

Wear of the central part of the tread

• The tires are overinflated.

Wear of the inner and outer edges of the tread

• The tires are not inflated enough.
• The shock absorbers are worn out.

Uneven tread wear

• The tire/wheel balance is disturbed.
• Excessive lateral runout of the wheel or tire.
• The shock absorbers are worn out.
• The tire is damaged.

Diagnostics of faults of the tempostat

The main switch of the cruise control does not turn on

• Check the power supply.
• Check the main cruise control switch.

The temperature control is not set

• Check the SET/COAST switch.
• Check the brake light and parking light switch
• Check the clutch switch (manual transmission).
• Check the ignition switch (IS).
• Check the vehicle speed sensor (VSS).

The engine does not maintain the set speed ±3 km/h

• Check the vehicle speed sensor.

Vehicle speed does not increase or return to set speed after pressing RESUME/ACCEL switch

• Check the RESUME/ACCEL switch.

Vehicle speed does not decrease after pressing SET/COAST switch

• Check the SET/COAST switch.

The thermostat does not turn off after pressing the CANCEL switch

• Check the CANCEL switch.

The cruise control does not switch off after releasing the brake pedal

• Check the brake light and parking light switch.

The cruise control does not switch off after releasing the clutch pedal (manual transmission)

• Check the clutch switch.

Diagnostics of on-board electrical equipment failures

One or both headlights are not functioning properly in low or high beam mode

• The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the headlight unit and the serviceability of the power supply to it from the battery. If the power is supplied correctly and the grounding is in order, replace the faulty lamp. If the power supply/grounding is damaged, check the condition of the wiring of the corresponding circuit (see electrical connection diagrams).
• The control switch is faulty.

The brightness of one or both headlights is greatly reduced

• The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the headlight unit and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly low, check the condition of the components and connecting wiring of the corresponding circuit (see electrical connection diagrams).
• The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

Running lights and side lights

Running lights and side lights do not function

• The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the corresponding lighting device and the serviceability of the power supply to it from the battery. If the power is supplied correctly and the grounding is in order, check the condition of the socket, if necessary, replace the faulty lamp. If the power supply/grounding is damaged, check the condition of the wiring of the corresponding circuit (see electrical connection diagrams).
• The control switch is faulty. Replace it.

There are intermittent failures of running lights and side lights

• The filament of the corresponding lamp is damaged. Check and replace the defective lamp.
• The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.
• The wiring or its contact terminals are damaged. Check and make appropriate corrections.
• The control switch is faulty. Replace it.

The brightness of one of the lighting devices is greatly reduced

• The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the corresponding lighting device and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly underestimated, check the condition of the components and connecting wiring of the corresponding circuit (see electrical connection diagrams).
• The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.
• The control switch is faulty. Replace it.

Interior lighting fixtures

Interior lighting does not function

• The control switch is set to the wrong position. Find the switch and set it to the correct position.
• The quality of the contact connection on the lamp connector is damaged. Check the quality of the grounding and the serviceability of the power supply from the battery. If there is no power, check the condition of the corresponding fuse, replace it if necessary. Check the condition of the elements and connecting wiring of the corresponding circuit (see electrical connection diagrams). If there is no grounding, check the condition of the door sensor-switch contacts, remove traces of corrosion, and replace defective components if necessary.

There is an intermittent failure of the interior lighting

• The filament of the corresponding lamp is damaged. Check and replace the defective lamp.
• The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.
• The contact terminals of the external connector of the lamp are oxidized or damaged. Check, clean or replace the corresponding components.
• The door sensor switches are not functioning properly. Check and replace the faulty components.

The brightness of the interior lighting is greatly reduced

• The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the lamp and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly underestimated, check the condition of the elements and connecting wiring of the corresponding circuit (see electrical connection diagrams).
• The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.
• One of the control switches/sensors is faulty. Replace it.

Brake lights

There is a failure of one of the brake lights

• The voltage supply to the corresponding brake light bulb is faulty. Check if the power supply is correct, assess the grounding quality, and replace the bulb if necessary. If signs of a power or ground circuit break are detected, check the condition of the components and connecting wiring of the corresponding circuit (see electrical connection diagrams).

There is a failure of both brake lights

• The brake light switch sensor adjustment is out of order. Check and make the appropriate adjustment. If the power supply to the brake lights remains interrupted despite the correct operation of the switch sensor, check the condition of the components and the connecting wiring of the corresponding circuit (see electrical connection diagrams), make the necessary corrections.

The brightness of one or both brake lights is greatly reduced

• The quality of the contact connection on one of the contact connectors of the corresponding circuit is broken. Check the quality of the grounding of the lamp assemblies and the serviceability of the power supply to them from the battery. If the supply voltage on the connector is significantly underestimated, check the condition of the elements and connecting wiring of the corresponding circuit (see electrical connection diagrams). Sometimes it becomes necessary to remove a defective connector and clean its mounting surface.

Control lamps/indicator lights

The indicator lamp remains on after the engine has started.

Charge indicator light

• The generator or voltage regulator is faulty. Check and replace the faulty components.
• There is a short circuit in the wiring circuit of the corresponding lamp. Check and make the necessary corrections.

Malfunction Indicator Lamp MIL (Check Engine)

• It is time for the next engine maintenance, or the engine settings have been violated. Perform maintenance, check the settings, assess the condition of the spark plugs and air filter, check the level and condition of the engine oil. Make the necessary adjustments and replacements.
• There is an intermittent lean air-fuel mixture as a result of the fuel tank running low. Fill the car with fuel, reinstall the lamp.
• The quality of the contact connections in the injection/engine control system circuit is impaired. Check the condition of the electrical wiring and contact connectors of the control module and information sensors.
• There is a loss of vacuum in the intake manifold. Check the condition of the sealing gasket and vacuum hoses. Replace defective components.
• There is increased engine oil consumption due to severe wear of internal engine components. Perform a restorative overhaul of the power unit.

ABS warning light

• The contact connections of the wheel sensors are oxidized, or foreign particles are stuck between the teeth of the signal rotors. Check and make necessary corrections.
• There are leaks in the master cylinder. Inspect the cylinder, replace the failed seals and gaskets.
• The ABS control module, hydraulic pump or control valves are not functioning properly. Check the condition of the components, make the necessary corrections/replace defective parts.
• There is a fault in the electrical circuit of the wheel sensors/ABS control module. Carefully inspect the wiring, eliminate any defects found.

Brake system warning light

• The hydraulic fluid level in the brake master cylinder reservoir has dropped. Check the hydraulic circuit of the brake system for signs of leaks, eliminate any detected faults, and add the required amount of fluid of the required grade to the reservoir.
• The friction linings of the brake pads/shoes are excessively worn. Check and replace any defective components.

Attention! Replacement of brake pads/shoes is always carried out as a set for both wheels of the corresponding axle!

• There is a defect in the indicator lamp signal sensor circuit. Check, make necessary corrections, replace the faulty components.

Oil pressure warning light

Operating a vehicle with low oil pressure can result in serious internal engine damage, resulting in costly repairs!

One of the signs of an unacceptable decrease in oil pressure is an increase in detonation during engine operation.

• When this warning light comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add the appropriate amount of oil from the canister that should be kept in the car and renewed at each oil change.
• The wiring of the oil pressure warning lamp sensor-switch is damaged. With the ignition on (do not start the engine) disconnect the wiring from the sensor switch - the control lamp should not light, otherwise check the wiring for signs of a short circuit to ground. Make sure the insulation is intact along the entire length of the wires, replace defective circuit elements.
• The oil intake mesh filter is clogged. Remove the oil pan and clean the filter.
• The oil pressure indicator lamp switch sensor is not functioning properly. To check, install a known good sensor.
• The full-flow oil filter is clogged or there are oil leaks. Replace the filter.

Parking brake engagement indicator light

• The parking brake lever is not released. Remember to release the parking brake before starting to move.
• The installation position of the control lamp switch sensor is disturbed, or there is a short circuit in its wiring circuit. Check and eliminate the detected faults.
• The indicator lamp switch sensor is faulty. Check and replace.

The indicator light starts flashing while driving

Charge indicator light

• The generator or voltage regulator is faulty. Check and replace the faulty components.
• There is a short circuit in the wiring circuit of the corresponding lamp. Check and make the necessary corrections.

MIL (Check Engine) Light

• It is time for the next engine maintenance, or the engine settings have been violated. Perform maintenance, check the settings, assess the condition of the spark plugs and air filter, check the level and condition of the engine oil. Make the necessary adjustments and replacements.
• There is an intermittent lean air-fuel mixture as a result of the fuel tank running low. Fill the car with fuel, reinstall the lamp.
• The quality of the contact connections in the injection/engine control system circuit is impaired. Check the condition of the electrical wiring and contact connectors of the control module and information sensors.
• There is a loss of vacuum in the intake manifold. Check the condition of the sealing gasket and vacuum hoses. Replace defective components.
• The wiring of the control lamp circuit is damaged. Check the wiring for short circuits, eliminate any detected faults.

ABS warning light

• The contact connections of the wheel sensors are oxidized, or foreign particles are stuck between the teeth of the signal rotors. Check and make necessary corrections.
• There are leaks in the master cylinder. Inspect the cylinder, replace the failed seals and gaskets.
• The ABS control module, hydraulic pump or control valves are not functioning properly. Check the condition of the components, make the necessary corrections/replace defective parts.
• There is a fault in the electrical circuit of the wheel sensors/ABS control module. Carefully inspect the wiring, eliminate any defects found.

Brake system warning light

• The hydraulic fluid level in the brake master cylinder reservoir has dropped. Check the hydraulic circuit of the brake system for signs of leaks, eliminate any detected faults, and add the required amount of fluid of the required grade to the reservoir.
• The friction linings of the brake pads/shoes are excessively worn. Check and replace any defective components.

• Attention! Replacement of brake pads/shoes is always carried out as a set for both wheels of the corresponding axle!

• There is a defect in the indicator lamp signal sensor circuit. Check, make necessary corrections, replace the faulty components.

Oil pressure warning light

Warning! Operating a vehicle with low oil pressure can result in serious internal engine damage, which will require costly repairs.

One of the signs of an unacceptable decrease in oil pressure is an increase in detonation during engine operation.

• When this warning light comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add the appropriate amount of oil from the canister that should be kept in the car and renewed at each oil change.
• The wiring of the oil pressure warning lamp sensor-switch is damaged. With the ignition on (do not start the engine) disconnect the wiring from the sensor switch - the control lamp should not light, otherwise check the wiring for signs of a short circuit to ground. Make sure the insulation is intact along the entire length of the wires, replace defective circuit elements.
• The oil intake mesh filter is clogged. Remove the oil pan and clean the filter.
• The oil pressure indicator lamp switch sensor is not functioning properly. To check, install a known good sensor.

Parking brake engagement indicator light

• The parking brake lever is not released. Remember to release the parking brake before starting to move.
• The installation position of the control lamp switch sensor is disturbed, or there is a short circuit in its wiring circuit. Check and eliminate the detected faults.
• The indicator lamp switch sensor is faulty. Check and replace.

The indicator lamp does not light when the ignition is turned on without starting the engine

• The lamp is faulty - check by substituting a known good one.
• There is a break in the circuit. Check the condition of the corresponding electrical wiring.
• The corresponding sensor-switch is faulty, or there is a defect in its wiring circuit. Check, eliminate the detected faults, replace the defective components.

Direction indicators hazard warning lights

The signal lights come on but operate continuously

• The breaker is faulty. Replace the faulty unit.

There is a two-way failure of the signal lights

• The fuse has blown. Check and replace.
• The circuit breaker is out of order - check by substituting a known good unit.
• There is a fault in the electrical wiring circuit. Check and correct any faults found.

There is a one-sided failure of the signal lights

• The lamps are burnt out. Check and replace the defective lamps.
• The quality of grounding of the assemblies of the corresponding lights is broken. Check, eliminate the break.

Only one of the signal lights does not turn on

• The lamp is burnt out. Check and replace.
• The contact surfaces of the base/cartridge are oxidized. Check and clean the terminals.
• The quality of the grounding of the socket of the corresponding lamp is broken. Check and eliminate the break.

The frequency of flashing signal lights is greatly reduced

• The lamps installed are too powerful. Replace the lamps.

The frequency of flashing signal lights has increased significantly

• The lamps installed are not powerful enough. Replace the lamps.
• The breaker is the wrong type. Replace the breaker.

The hazard warning light is not functioning properly

• The corresponding external signal lights are faulty. Check and replace the indicator lamp if necessary.
• The hazard warning switch is faulty. Check and replace if necessary.

One of the direction indicator lamps is not functioning properly

• The lamp is burnt out. Check and replace.
• The breaker is faulty - check by substituting a known good unit, replace if necessary.

Horn

There is no sound signal

• The corresponding fuse has blown. Check and replace if necessary.
• The power supply to the horn is faulty, or there is a break in the ground circuit. Check. If the power supply is correct, replace the horn. If a fault is detected, check the condition of the corresponding electrical wiring.

The tone of the horn has changed

• On models with one horn, replace the latter.
• On models with a 2-horn horn, check the correct operation of the second horn. Disconnect the wiring from the horns one by one and check the correct operation of each of them separately. Replace the failed component.
• Check the correct installation of the horn - the horns should be installed with the bell facing down. Make sure that no foreign objects have gotten inside the horn.

Windscreen wipers

Windscreen wipers do not work

• The fuse has blown. Check and replace.
• The control switch is faulty. Check, fix any problems found, replace the switch if necessary.
• The quality of the contact connections in the windshield wiper drive circuit is damaged. Check, clean the terminals, replace the faulty elements.
• The quality of the grounding of the control switch or the drive electric motor is broken. Check and eliminate any detected breaks.

The drive electric motor overheats, turning on the windshield wipers causes the fuse to blow

• There is internal damage to the electric motor. Replace it.
• The wiper arm drive rods are jammed or deformed. Check, make necessary corrections, replace the faulty components.

One or both windshield wiper arms are not functioning properly, although the drive motor is working properly

• The fastener of the corresponding drive rod is loose. Check and tighten the fastener.
• The lever mount on the drive axle has become loose. Tighten the nut, if necessary, replace the corresponding lever/drive axle assembly.

When switched off, the brushes do not return to the parking position

• As a result of a control switch malfunction, the order of power supply disconnection from the drive electric motor is disrupted. Check and eliminate the detected malfunctions.
• There is a fault in the drive motor parking circuit. Replace the electric motor. Before installing the levers, start the system to determine the correct parking position of the windshield wipers. After completing the installation, turn on the windshield wipers at maximum speed and make sure that the brushes do not hit the window frame trim in their extreme positions.

Diagnostics of instrument cluster failures

The speedometer is completely out of order

• Drive cable not properly connected to gauge assembly or pinion gear. Check and make necessary corrections.
• The drive cable is broken or the ends that secure it to the meter/drive pinion assembly are rounded. Check and replace if necessary.
• The speedometer pinion is worn. Check and replace if necessary.
• The meter is faulty - check by substituting a known good assembly. Replace if necessary.

There are fluctuations in the meter needle when moving at a constant speed

• The cable is not routed correctly, there are kinks or twists. Check, make the necessary corrections, and if signs of damage to the sheath are detected, replace the cable.
• The cable assembly needs lubrication. Remove the cable and inspect it for damage (replace if necessary), lubricate and install in place.

There are intermittent disturbances in the speedometer operation

• The cable connection is not complete and the cable is not securely fixed in the clamps. Check and make the necessary corrections.
• The cable ends are worn (rounded). Check and replace the cable assembly if necessary.

Electric speedometer

The speedometer is completely out of order

• The inductive output of the speed sensor (VSS) is faulty. Replace the sensor.
• The wiring in the circuit section between the VSS and the speedometer is damaged. Inspect the wiring, assess the quality of the contact connections, eliminate the identified faults, replace the defective components.
• The meter is damaged, check by substituting a known good assembly. Replace if necessary.

There are intermittent disturbances in the speedometer operation

• The quality of the contact connections in the circuit section between the VSS and the speedometer is damaged. Check, make necessary corrections, replace defective components.
• The inductive drift of the speed sensor (VSS) is faulty. Replace the sensor.

Fuel gauges and engine temperature gauges

The functioning of the meter is completely disrupted

• The corresponding fuse has blown. Check and replace.
• There is a break in the wiring circuit of the corresponding meter. Check and eliminate the detected faults.
• The corresponding sensor is faulty. Check and replace.
• The installation of the meter or its sensor is incorrect. Check and make appropriate corrections.

The stability of the meter readings is disrupted

• The quality of the contact connections of the corresponding electrical circuit is damaged. Check and eliminate any detected faults.
• The meter is faulty. Replace it.

The meter continuously records the maximum reading

• There is a short circuit to ground in the wiring circuit of the corresponding meter.
• The meter is faulty. Replace it.
• The meter's grounding is faulty. Check and fix the break.
• The installation of the meter or its sensor is incorrect. Check and make appropriate corrections.

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