3: ABS Light Stays on After the Engine Is Started

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.

ABS Warning Light Circuit
2: When Ignition "on" (Engine Stopped the ABS Light Stays Off

CIRCUIT OPERATION
2: When Ignition "on" (Engine Stopped the ABS Light Stays Off

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably the ABS-ECU malfunction.

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

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set





STEP 1. Check the wiring harness between the ASS warning light relay and the ABS warning light.
1) Disconnect ABS warning light relay connector C-213.
2) Turn the ignition switch to the "ON" position.
Q: Does the ABS warning light illuminate?
YES: Go to Step 2.
NO: Go to Step 3.








STEP 2. Check the continuity between the combination meter and the ASS warning light relay.

NOTE: After inspecting combination meter connector C-01 and ABS warning light relay connector C-213, inspect the wire. If combination meter connector C-01 or ABS warning light relay connector C-213 is damaged, repair or replace it. If the connector has been repaired or replaced, go to Step 8.

Q: Is the harness wire between combination meter connector C-01 and ABS warning light relay connector C-213 damaged?
YES: Replace the combination meter (printed circuit board) and then go to Step 8.
NO: Repair the harness wire and then go to Step 8.

STEP 3. Check the ABS warning light relay.





1) Remove the ABS warning light relay.





2) Check the continuity between terminals 2 - 5 when battery voltage is applied between terminals 1 - 3.
Q: Is the ABS warning light relay continuity?
YES: Go to Step 4.
NO: Replace it and then go to Step 8.








STEP 4. Check the ABS warning light relay power supply circuit
1) Disconnect ABS warning light relay connector C-213.
2) Turn the ignition switch to the "ON" position.
3) Measure the voltage between terminal 1 and ground. It should be approximately 12 volts (battery positive voltage).
Q: Is the voltage approximately 12 volts (battery positive voltage)?
YES: Go to Step 6.
NO: Go to Step 5.





STEP 5. Check the continuity between connector C-214 and the ABS warning light relay.

NOTE: After inspecting connector C-214 and ABS warning light relay connector C-213, inspect the wire. If connector C-214 or ABS warning light relay connector C-213 is damaged, repair or replace it. If the connector has been repaired or replaced, go to Step 8.

Q: Is the harness wire between the connector C-214 and the ABS warning light relay connector C-213 continuity?
YES: Go to Step 8.
NO: Repair the harness wire and then go to Step 8.








STEP 6. Check the ABS warning light circuit at ABS-ECU connector B-118.
1) Disconnect ABS-ECU connector B-118.
2) Connect ABS-ECU connector B-118 terminal number 12 to ground.
3) Turn the ignition switch to the "ON" position.
Q: Does the ABS warning light go off?
YES: Replace the hydraulic unit (integrated with ABS-ECU) and the go to Step 8.
NO: Go to Step 7.








STEP 7. Check the harness wire between ABS-ECU connector B-118 and ABS warning light relay connector C-213.
Q: Is the harness wire between ABS-ECU connector B-118 and ABS warning light relay connector C-213 damaged?
YES: Repair it and then go to Step 8.
NO: Go to Step 8.

STEP 8. Check symptoms.
Q: Does the ABS warning light turn off in 3 seconds after start-up?
YES: This diagnosis is complete.
NO: Return to Step 1.