Inspection Procedure 3

INSPECTION PROCEDURE 3: The ABS Warning Light Remains Illuminated After the Engine is Started.

NOTE: This diagnosis procedure is limited to cases where communication with the scan tool is possible (ABS-ECU power supply is normal) and no diagnostic trouble code outputs.

















CIRCUIT OPERATION
- The ABS-ECU controls the illumination of the ABS warning light by turning the power transistor in the control unit ON and OFF
- The ABS-ECU illuminates the ABS warning light on start-up. It turns the light off after 3 seconds when the ABS-ECU completes the self-check.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably the ABS-ECU and hydraulic unit assembly malfunction.

TROUBLESHOOTING HINTS (The most likely causes for this condition:)
- Damaged wiring harness
- Malfunction of the hydraulic unit (integrated with ABS-ECU)

DIAGNOSIS
Required Special Tool:
- MB991223: Harness Set








STEP: 1. Check the harness wires between ABS-ECU connector A-02 and combination meter connector C-102.
Q:Is the harness wire between ABS-ECU connector A-02 and combination meter connector C-102 damaged?
YES:Repair it and then go to Step 3.
NO:Go to Step 2.





STEP: 2. Check the harness wires between ABS-ECU connector A-02 and ground.
Q:Is the harness wire between ABS-ECU connector A-02 and ground damaged?
YES:Repair it and then go to Step 3.
NO:Replace the ABS-ECU and then go to Step 3.
STEP: 3. Check symptom.
Q:Does the ABS warning light turn off 3 seconds after start-up?
YES:This diagnosis is complete.
NO:Return to Step 1.