Information about diagnostic tools
Checking the correct functioning of the components of the injection systems and reducing the toxicity of exhaust gases is carried out using a universal digital meter (multimeter). The use of a digital meter is preferred for several reasons. Firstly, it is quite difficult for analog devices to (sometimes impossible), to determine the result of the indication with an accuracy of hundredths and thousandths, while when examining circuits that include electronic components, such accuracy is of particular importance. The second, no less important, reason is the fact that the internal circuit of a digital multimeter has a fairly high impedance (the internal resistance of the device is 10 million ohms). Since the voltmeter is connected in parallel to the circuit under test, the measurement accuracy is the higher, the less parasitic current will pass through the device itself. This factor is not significant when measuring relatively high voltage values (9÷12 V), however, it becomes decisive in the diagnosis of elements that produce low-voltage signals, such as, for example, an oxygen sensor, where it is a matter of measuring fractions of a volt.
The most convenient device for diagnosing engine control systems of modern car models are manual scanner-type readers. First generation scanners are used to read fault codes for OBD-I systems. Before use, the reader should be checked for compliance with the model and year of manufacture of the vehicle being checked. Some scanners are multifunctional, due to the possibility of changing the cartridge depending on the model of the car being diagnosed (Ford, GM, Chrysler, etc.), others are tied to the requirements of regional authorities and are intended for use in certain areas of the world (Europe, Asia, USA, etc.).
With the introduction of a second-generation on-board diagnostic system that meets the latest environmental legislation (OBD-II) Readers of a special design began to be produced. Some manufacturers have launched scanners designed for use by amateur mechanics at home - ask in car accessories stores. In principle, reading the fault codes recorded in the memory of the self-diagnosis system can be done using a jumper wire installed between specific terminals of the 16-pin diagnostic connector.
General description of the OBD system
The OBD system includes several diagnostic devices that monitor individual parameters of the toxicity reduction systems and fix the detected failures in the on-board processor memory in the form of individual fault codes. The system also checks sensors and actuators, controls the vehicle's operating cycles, provides the possibility of freezing parameters and clearing the memory block.
All models described in this manual are equipped with a second generation on-board diagnostic system (OBD-II). The main element of the system is the onboard processor, often called the electronic control module (ECM), or a power unit operation control module (RSM). The PCM is the brain of the engine management system. The initial data is fed to the module from various information sensors and other electronic components (switches, relays, etc.). Based on the analysis of the data coming from the information sensors and in accordance with the basic parameters stored in the processor memory, the PCM generates commands for the operation of various control relays and actuators, thereby adjusting the operating parameters of the engine and ensuring maximum efficiency of its output with minimum fuel consumption. The OBD-II processor memory data is read using a special scanner connected to the 16-pin diagnostic connector for reading the database (DLC), located under the instrument panel on the driver's side of the vehicle.
Note. In principle, reading the fault codes recorded in the memory of the self-diagnosis system can be done using a jumper wire installed between specific terminals of the 16-pin diagnostic connector.
Engine management/emission control system components are subject to a special extended warranty. You should not attempt to independently diagnose PCM failures or replace system components until the expiration of this obligation - contact Honda authorized service stations.
Information sensors
oxygen sensors (l-probes) - The sensor generates a signal whose amplitude depends on the difference in oxygen content (About 2) in engine exhaust gases and outside air.
crankshaft position sensor (TFR) - The sensor informs the PCM about the position of the crankshaft and the engine speed. This information is used by the processor when determining fuel injection timing and setting the ignition timing.
Piston position sensor (CYP) - Based on the analysis of the signals coming from the sensor, the PCM calculates the position of the piston of the first cylinder and uses this information to determine the moments and sequence of fuel injection into the engine's combustion chambers.
TDC sensor (TDC) - The signals generated by the sensor are used by the PCM in determining the ignition timing settings at the time of engine start.
Engine coolant temperature sensor (EATING) - Based on the information coming from the sensor, the ECM / PCM makes the necessary adjustments to the composition of the air-fuel mixture and the ignition timing, and also monitors the operation of the EGR system.
intake air temperature sensor (IAT) - The PCM uses information from the IAT sensor to make adjustments to fuel flow, ignition timing settings, and to control the operation of the EGR system.
Throttle position sensor (TPS) - The sensor is located on the throttle body and connected to the throttle shaft. Based on the amplitude of the TPS signal output, the PCM determines the throttle opening angle (controlled by the driver from the gas pedal) and adjusts the fuel supply to the inlet ports of the combustion chambers accordingly. The failure of the sensor, or the weakening of its fastening, leads to interruptions in injection and violations of the stability of the idle speed.
Absolute pressure sensor in the pipeline (IDA) - The sensor monitors variations in the depth of vacuum in the intake manifold associated with changes in crankshaft speed and engine load and converts the information received into an amplitude signal. The PCM uses the information provided by the MAP and IAT sensors to make subtle fuel adjustments.
Barometric pressure sensor - The sensor generates an amplitude signal proportional to changes in atmospheric pressure, which is used by the PCM to determine the duration of the fuel injection moments. The sensor is built into the PCM and cannot be serviced individually.
Knock sensor - The sensor reacts to changes in the level of vibrations associated with detonations in the engine. Based on the information coming from the sensor, the PCM performs an appropriate adjustment of the ignition timing.
Vehicle speed sensor (VSS) - As its name implies, the sensor informs the processor about the current vehicle speed.
EGR valve opening sensor - The sensor notifies the PCM of the amount of displacement of the EGR valve plunger. The information received is then used by the processor when controlling the operation of the exhaust gas recirculation system.
Fuel tank pressure sensor - The sensor is an integral element of the fuel vapor recovery system (EVAP) and serves to monitor the vapor pressure of gasoline in the tank. Based on the information coming from the sensor, the PCM issues commands to operate the system purge solenoid valves.
Power steering pressure switch (PSP) - Based on the information coming from the PSP sensor-switch, the PCM provides an increase in idle speed due to the operation of the IAC sensor in order to compensate for the increased engine loads associated with the operation of the power steering during maneuvers.
Transmission sensors - In addition to the data coming from the VSS, the PCM also receives information from sensors placed inside the gearbox or connected to it. These sensors include: (A) secondary speed sensor (indigenous) shaft and (b) intermediate shaft speed sensor.
Sensor-switch for controlling the inclusion of the clutch clutch of the air conditioner - When battery power is applied to the K / V compressor solenoid valve, the corresponding information signal is sent to the PCM, which regards it as evidence of an increase in the load on the engine and adjusts its idling speed accordingly.
Executive devices
Main relay PGM-FI (fuel pump relay) - The PCM activates the fuel pump relay when the ignition key is turned to the START or RUN position. When the ignition is turned on, the activation of the relay provides a pressure rise in the power system. For more information on the main relay, see Chapter Power and exhaust systems.
Fuel Injectors - PCM ensures that each of the injectors is switched on individually in accordance with the established firing order. In addition, the module controls the duration of the opening of the injectors, determined by the width of the control pulse, measured in milliseconds, which determines the amount of fuel injected into the cylinder. More detailed information on the principle of operation of the injection system, replacement and maintenance of injectors is given in Chapter Power and exhaust systems.
Ignition control module (ICM) - The module controls the functioning of the ignition coil, determining the required basic advance based on the commands generated by the PCM. On all models of cars considered in this Manual, the ICM built into the ignition distributor is used, for more details see Chapter Engine electrical equipment.
Idle speed control valve (IAC) - The IAC valve controls the amount of air bypassing the throttle when the throttle is closed or in the idle position. The opening of the valve and the formation of the resulting air flow is controlled by the PCM.
Carbon canister purge solenoid valve - The valve is an integral part of the fuel vapor recovery system (EVAP) and, triggered by the command of the PCM, releases the fuel vapors accumulated in the adsorber into the intake pipeline in order to burn them during the normal operation of the engine.
Carbon canister purge control solenoid - The solenoid is used by the PCM when the OBD-II system checks that the EVAP system is functioning properly.
Reading trouble codes
1. If a malfunction is detected that repeats in a row during the spirit of trips, the PCM issues a command to turn on the warning lamp built into the instrument panel "Check engine", also called the failure indicator. The lamp will continue to burn until the memory of the self-diagnosis system is cleared of the fault codes entered in it. Reading trouble codes in the OBD-II system can be done in two different ways. The first method requires a jumper wire between terminals No. 8 and 13 of the 16-pin database connector (DLC). In the second case, reading is performed using a special scanner, the interface of which allows you to connect it to the 16-pin DLC connector of the OBD-II system. The following is a detailed description of the method for reading codes using a jumper wire. If necessary, the procedure can be entrusted to car service specialists.
2. Without starting the engine, turn on the ignition, - control lamp "Check engine" should light up, otherwise it should be replaced. After checking the serviceability of the lamp, turn off the ignition again.
3. Find the 16-pin DLC diagnostic connector on the left under the instrument panel and, with a jumper wire, replace its terminals No. 8 and 13 with each other.
Note. Be careful not to damage the terminals.
4. Switch on the ignition by turning the key to the ON position. If the codes of the faults that have occurred are entered in the processor memory, they will start to be sequentially displayed by the control lamp "Check engine" on the car's dashboard. The first digit of the two-digit code is displayed with long flashes of the lamp, the second - with short ones (for example, one long flash followed by six short flashes corresponds to code 16).
Note. If more than one code is stored in the memory of the control module, they will be displayed one by one, then, after a pause, the codes will be displayed again. If the system memory is clear, the indicator lamp will not turn on.
Clearing ECM/PCM Memory
1. When a fault code is entered into the PCM memory, a warning lamp lights up on the vehicle's instrument panel "Check engine". The code remains stored in the module's memory until the power is removed from it. To clear the module memory, turn off the ignition and remove fuse No. 13 for 10÷15 seconds (BACK-UP) 7.5 A from the mounting block located on the right side of the engine compartment (see chapter Onboard electrical equipment). If necessary, the procedure for clearing the memory of the OBD system can be entrusted to car service specialists.
Note. Do not clear the OBD memory by disconnecting the negative cable from the battery, as this will erase the engine settings and make the engine rpm unstable during the first time after the initial start.
2. Make sure the system memory is cleared before installing new emission control system components on the engine. If the fault memory is not cleared before starting the system after replacing a failed information sensor, the PCM will enter a new fault code into it. Clearing memory allows the processor to reconfigure to new parameters. In this case, in the first 50–20 minutes after the initial start of the engine, some violation of the stability of its revolutions may occur.
List of OBD-II Self-Diagnostic System Fault Codes
Code number (number of flashes of the control lamp) | Possible reason for rejection |
P0107 (3) | MAP sensor input low |
P0108 (3) | MAP sensor input high |
Р0112 (10) | Low IAT sensor input |
Р0113 (10) | IAT sensor input high |
P0116 (86) | ECT sensor/engine efficiency problems |
P0117 (6) | Low ECT Sensor Input |
P0118 (6) | ECT Sensor High Input |
P0122 (7) | Low TPS sensor input |
P0123 (7) | TPS sensor input high |
P0131 (1) | Low voltage of the primary heated λ-probe circuit (oxygen sensor 1) |
P0132 (1) | High voltage of the primary heated λ-probe circuit (oxygen sensor 1) |
P0133 (61) | Slow response of the primary heated λ-probe (oxygen sensor 1) |
P0135 (41) | Malfunction in the circuit of the primary λ-probe (oxygen sensor 1) |
P0137 (63) | Secondary heated λ-probe circuit low voltage (oxygen sensor 2) |
P0138 (63) | Secondary heated λ-probe circuit high voltage (oxygen sensor 2) |
P0139 (63) | Slow response of the secondary heated λ-probe (oxygen sensor 2) |
P0141 (65) | Malfunction in the heater circuit of the secondary λ-probe (oxygen sensor 2) |
P0171 (45) | Relean mixture |
P0172 (45) | Re-enrichment of the mixture |
P0300 (71) | Random misfires |
P0301 (71) | Cylinder #1 Misfire |
P0302 (72) | Cylinder #2 Misfire |
P0303 (73) | Cylinder #3 Misfire |
Р0304 (74) | Cylinder #4 Misfire |
P0305 (75) | Cylinder #5 Misfire (V6 models) |
P0306 (76) | Cylinder #6 Misfire (V6 models) |
P0325 (23) | Malfunction in a chain of the gauge of a detonation (4-cylinder models) |
P0335 (4) | Malfunction in the CKP sensor circuit |
P0336 (4) | TFR sensor |
P0401 (80) | Too little EGR flow detected |
Р0420 (67) | Insufficient efficiency of the catalytic converter |
Р0452 (91) | Low fuel tank pressure sensor input (EVAP system) |
P0453 (91) | Fuel Tank Pressure Sensor High Input (EVAP system) |
P0500 (17) | Fault in the VSS circuit (4-cylinder models with manual transmission) |
P0505 (14) | Malfunction in the IAC sensor circuit |
P0715 (70) | AT malfunction |
P0720 (70) | AT malfunction |
P0725 (70) | AT malfunction |
P0730 (70) | AT malfunction |
P0740 (70) | AT malfunction |
P0753 (70) | AT malfunction |
P0758 (70) | AT malfunction |
P0763 (70) | AT malfunction |
R1106 (13) | barometric sensor |
R1107 (13) | Barometric Sensor Input Low |
R1108 (13) | High barometric sensor input |
R1121 (7) | Low TPS sensor input |
R1122 (7) | TPS sensor input high |
R1128 (5) | The absolute pressure in the pipeline is lower than expected (MAP sensor input low) |
R1129 (5) | The absolute pressure in the pipeline is higher than expected (MAP sensor input high) |
R1149 (61) | Primary λ probe failure (4-cylinder models) |
R1162 (48) | Malfunction in the circuit of the primary λ-probe (4-cylinder models) |
R1163 (61) | Primary λ probe response too slow (4-cylinder models) |
R1164 (61) | Primary λ probe failure (4-cylinder models) |
R1165 (61) | Primary λ probe failure (4-cylinder models) |
R1166 (41) | Primary λ probe failure (4-cylinder models) |
R1167 (41) | Malfunction in the heater circuit of the primary λ-probe (4-cylinder models) |
R1253 (21) | VTEC system malfunction (4-cylinder models) |
R1257 (22) | VTEC system malfunction (4-cylinder models) |
R1258 (22) | VTEC system malfunction (4-cylinder models) |
R1259 (22) | VTEC system malfunction |
R1297 (20) | Low ELD input |
R1298 (20) | High ELD input |
R1359 (8) | CKP/TDC sensor disconnected |
R1361 (8) | TDC sensor instability |
R1362 (8) | No signal from TDC sensor |
R1366 (58) | Instability of TDC-2 sensor readings (V6 models) |
R1367 (58) | No signal from TDC sensor (V6 models) |
R1381 (9) | CYP sensor instability (4-cylinder models) |
R1381 (9) | No signal from CYP sensor (4-cylinder models) |
R1456 (90) | There are fuel vapor leaks in the gas tank (EVAP) |
R1457 (90) | There are fuel vapor leaks in the carbon adsorber (EVAP) |
R1491 (12) | Insufficient degree of opening of the EGR valve |
R1498 (12) | The EGR valve opening sensor outputs too high a signal |
R1519 (14) | Malfunction in the IAC valve circuit |
R1607 (-) | PCM Internal Circuit Malfunction |
R1705 (-) | AT malfunction |
R1706 (-) | AT malfunction |
R1738 (-) | AT malfunction |
R1739 (-) | AT malfunction |
R1753 (-) | AT malfunction |
R1768 (-) | AT malfunction |
R1773 (-) | AT malfunction |
R1791 (-) | AT malfunction |