ABS indicator lamp
1. The ABS indicator light comes on when the ABS control unit detects a problem in the system. However, even if the system is OK, the lamp will also light up under the following conditions.
- Fault signal
- Fast wheel rotation
- Rotation of drive wheels only
- Battery voltage fluctuations
2. When a problem is detected, the ABS indicator light comes on and stays on until» until the ignition switch is turned off and may go out automatically depending on the mode.
The lamp stays 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 certain case, the ABS indicator light is on» when the system turns on without clearing the DTC after fixing the problem, but goes off after starting the car.
When the wheel sensor system is faulty and the ABS indicator light comes on» The system algorithm automatically turns off the ABS indicator lamp» After that» as 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 light does not come on.
4. The control circuit of the ABS indicator lamp is of two categories as described below.
- EU model: When the control unit outputs battery voltage to the instrument panel, 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 what model you have and refer to the circuit diagram before you start troubleshooting.
Diagnostic trouble code (DTC)
1. Diagnostic trouble code (DTC) is remembered when a problem is detected and the indicator lamp does not go out or when the indicator lamp lights up. Therefore, the DTC is not remembered when the ABS indicator lamp comes on until the CPU is turned on.
2. Diagnostic trouble codes can be stored in such a quantity» in which they appear. However, if the same code is specified twice or more often, the later one is written over 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 in which they appear.
4. DTCs are stored in EEPROM (no lost memory)
Therefore, stored DTCs cannot be erased by the battery* Follow the specified 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 for ABS control: executed when ABS is not functioning.
- During ABS control: Executed when ABS is operating.
- During warning: Executed when the ABS indicator lamp is ON.
2. The system performs 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 deceleration control mode.
Recoil
1. The engine is running when the ABS is operating and the fluid in the fill barrel is pushed towards the master cylinder, causing kickback.
Therefore, the brake pedal must be depressed when kickback occurs, as is done 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 solenoid operating sound, but this is normal.
Pump motor
1. The pump motor runs when the ABS is operating.
2. The ABS control unit monitors engine operation during acceleration. You may hear a faint operating sound at this time, this is normal.
Malfunctions
1. Troubleshooting diagrams explain the operating procedure based on the assumption that the cause of the problem persists and the ABS indicator light does not go out but remains on. Please note that troubleshooting according to the diagram when the indicator lamp does not light up 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 other than ABS control, during ABS control, during acceleration, during specified engine speed, etc. Therefore, symptoms cannot be tested until the test conditions match the problem conditions.
3. When the ABS indicator lamp does not light up during the driving test, but the troubleshooting procedure is completed with DTC, check the connectors for looseness, poor pin connection, etc. before troubleshooting.
4. After troubleshooting, erase the DTC and check the car in motion. Make sure the ABS indicator light does not come on.
5. The connector symbol indicated in the pin description represents "sockets" contacts with single frame and "forks" double frame contacts.
6. Connector contact numbers "sockets" are marked on the wire side, and the numbers "forks" marked on the contact side.