4: TCL Warning Light Remains Illuminated After Starting Engine

CIRCUIT OPERATION
- The ABS-ECU controls the illumination of the TCL indicator light by turning it "ON" and "OFF."
- The ABS-ECU illuminates the TCL indicator light on start-up. If turns off the light after 3 seconds when the ABS-ECU completes the self-check.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably the hydraulic unit (integrated with ABS-ECU) 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 power supply circuit at the ABS-ECU connector A-02.
Disconnect ABS-ECU connector A-02. If the TCL indicator light illuminates, go to Step 2.
If it does not illuminate, replace the ABS-ECU. Then go to Step 3.





STEP 2. Check the harness wires between ABS-ECU connector A-02 and TCL indicator light connector C-1.
If any harness wires between ABS-ECU connector A-02 and TCL indicator light connector C-41 are damaged, repair them. Then go to Step 3.

STEP 3. Check symptom
Confirm the TCL indicator light turns off 3 seconds after start-up.