ABS indicator
1. If the system is OK, the ABS indicator goes out two seconds after the ignition key is turned to the ON position (II) without starting the engine, then lights up again and goes out after two seconds. This is because the ABS control unit is powered by the IG2 power supply.
2. The ABS indicator lights up when the ABS control unit detects a malfunction in the system. However, although the system is operating normally, the ABS indicator will also come on under the following conditions:
- Signal interference
- Wheel slip
- Drive wheels only rotate
- Fluctuations in battery voltage To determine the actual cause of the malfunction, it is necessary to know exactly the conditions for the indicator to light up
3. When a malfunction is detected and the ABS indicator lights up, there are times when the indicator stays on until the ignition key is turned to the OFF position and cases when the indicator goes off automatically when the system returns to normal. In the case of DTC 61, the indicator turns off automatically when the system returns to normal. For all other codes, the indicator stays on until the ignition key is turned to the OFF position.
4. The ABS light stays on when the system is re-enabled without clearing the DTC, but turns off after the engine is started. If the wheel sensor system is faulty and the ABS light comes on, the system algorithm will automatically turn off the ABS light after the wheel speed signal returns to normal. Also, when the DTC is cleared, the CPU resets and the ABS light turns off when the initial diagnostic confirms that the system is OK.
Therefore, after servicing the wheel sensor system, road test the vehicle and verify that the ABS indicator does not come on.
5. When the ABS control unit applies battery voltage to the instrument cluster, the ABS indicator goes off.
Diagnostic Trouble Codes (DTC)
1. Diagnostic trouble code (DTC) memorized when a malfunction is detected and when the ABS indicator does not go out or when the ABS indicator lights up. DTC (DTC) is not entered into memory when the ABS indicator is lit unless the CPU is being driven.
2. Any number of DTCs can be stored in memory. However, when the same DTC is detected two or more times, the old code is overwritten with the new one. Thus, if the same malfunction occurs repeatedly, it is recorded as one DTC.
3. DTCs are displayed in ascending order of number, not in the order in which they occur.
4. DTCs are written to EEPROM (non-volatile memory).
Therefore, stored DTCs cannot be cleared by disconnecting the battery. Follow the required procedures to clear the DTCs.
Self-diagnosis
1. Self-diagnosis can be divided into the following four categories:
- Primary diagnosis: performed immediately after starting the engine until the ABS indicator goes out.
- Without ABS control: performed when the ABS system is not active.
- With ABS control: performed when the ABS system is active.
- On Warning: Executed when the ABS indicator is on.
2. When a malfunction is detected during self-diagnosis, the system performs the following actions.
- Illuminates the ABS indicator
- Stores the DTC code
- Stops the ABS system