Precautions for troubleshooting (Honda Civic 5)

ABS indicator lamp

1. The ABS indicator lamp lights up when the ABS control unit detects a problem in the system. However, even if the system is normal, the lamp also lights up under the following conditions.

• Malfunction signal
• Fast wheel rotation
• Rotation of only the drive wheels
• Battery voltage fluctuations

2. When a problem is detected, the ABS indicator lamp comes on and stays on until the ignition switch is turned off and may go out automatically depending on the mode.

The lamp remains on until the ignition switch is turned off:

• When the system is in system failure mode.

The lamp turns off automatically:

• When the system is in deceleration control mode (refer to the symptom-system table).

3. In some cases, the ABS indicator light comes on when the system is turned on without clearing the DTC after correcting the problem, but goes out after the car is started.

When the wheel sensor system is faulty and the ABS indicator lamp lights up, the system algorithm automatically turns off the ABS indicator lamp after the wheel speed signal returns to normal. When the DTC is cleared (erased), the CPU is reset and the ABS indicator lamp goes out when the system is found to be normal by the initial diagnosis. Therefore, perform a driving test after servicing the wheel sensor system and make sure that the ABS indicator lamp does not light up.

4. ABS indicator lamp control circuit has two categories as described below.

• EU model: When the control unit outputs battery voltage to the instrument cluster, the ABS indicator lamp goes out.
• Except EU model: When the control unit cuts off the current from the instrument panel, the indicator lamp goes out.

Therefore, make sure which model you have and refer to the circuit diagram before you begin troubleshooting.

Diagnostic Trouble Code (DTC)

1. A diagnostic trouble code (DTC) is stored when a problem is detected and the indicator lamp does not go out or when the indicator lamp comes on. Therefore, a DTC is not stored when the ABS indicator lamp comes on until the CPU is turned on.

2. Diagnostic trouble codes can be stored as many times as they occur. However, if the same code is detected twice or more often, the later one will overwrite the previous one.

Therefore, if a problem is detected multiple times, it is recorded as one DTC.

3. DTCs are displayed in ascending numerical order, not in the order they appear.

4. DTC codes are stored in EEPROM (non-losable memory)

Therefore, stored DTCs cannot be cleared by the battery* Follow the established erasing procedure.

Self-diagnosis

1. Self-diagnosis can be classified into 4 categories.

• Initial diagnostics performed immediately after starting the engine until the ABS light goes out.
• Except ABS control: performed when ABS is not functioning.
• During ABS control: Performed when ABS is operating.
• During warning: Performed when the ABS indicator lamp is ON.

2. The system does the following when a problem is detected by self-diagnosis.

• Turns on the indicator lamp
• Remembers DTC
• The mode changes to system failure mode or slowdown control mode.

Recoil

1. The engine is running when the ABS is functioning and the fluid in the filler tank is pushed towards the brake master cylinder, causing kickback.

Therefore, the brake pedal must be depressed when kickback occurs, as it does during normal brake operation.

2. The ABS control unit controls the solenoid valve when the brake pedal is already released, after the initial diagnosis, at this time you can hear the sound of the solenoid working, but this is normal.

Pump motor

1. The pump motor runs when ABS is functioning.

2. The ABS control unit controls the engine operation during acceleration. At this time, you may hear a faint sound of operation, this is normal.

Malfunctions

1. Troubleshooting charts explain the procedure based on the assumption that the cause of the problem persists and the ABS indicator lamp does not go out but remains on. Note that troubleshooting according to the chart when the indicator lamp does not come on may lead to incorrect judgment.

2. Determine the condition under which the problem occurs and reproduce the same conditions for the malfunction.



Self-diagnosis is performed at various times, such as initial diagnosis except ABS control, during ABS control, during acceleration, during specified engine speed, etc. Therefore, the symptoms cannot be checked until the checking conditions match the conditions of the problem occurrence.

3. When the ABS indicator lamp does not light during the driving test but the troubleshooting procedure is completed with the DTC, check the connectors for looseness, poor contact connection, etc. before troubleshooting.

4. After troubleshooting, erase the DTC and test the car while driving. Make sure the ABS indicator lamp does not light.

5. The connector symbol shown in the contact description represents the "sockets" of single frame contacts and the "plugs" of double frame contacts.

6. The contact numbers of the socket connectors are indicated on the wire side, and the numbers of the plugs are indicated on the contact side.