Inspection Procedure 4: The ABS Warning Light Remains Illuminated After the Engine Is Started

INSPECTION PROCEDURE 3: When the Ignition Key is Turned to "ON" (Engine Stopped), the ABS Warning Light does not Illuminate.

INSPECTION PROCEDURE 4: The ABS Warning Light Remains Illuminated after the Engine is Started.








TECHNICAL DESCRIPTION (COMMENT)
^ The ABS-ECU sends the ABS warning light and the brake warning light signals to the combination meter via the CAN communication.
^ This may be caused by faults in the CAN bus line, the combination meter, or the ABS-ECU.

COMMENT
This may be caused by faults in the CAN bus line, the combination meter or the ABS-ECU.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
^ Damaged wiring harness or connector
^ Combination meter defective
^ Malfunction of the hydraulic unit (integrated with ABS-ECU)

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

CAUTION

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Diagnose the CAN bus line.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES: Go to Step 2
NO: Repair the CAN bus line. Then go to Step 4.

STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1) Turn the ignition switch to the "ON" position.
2) Erase the DTC.
3) Turn the ignition switch to the "LOCK" (OFF) position.
4) Turn the ignition switch to the "ON" position.
5) Check if the DTC is set.
6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?
YES: Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
Then go to Step 4.
NO: Go to Step 3.

STEP 3. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Check for Combination meter system diagnostic trouble code.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1102 set?
YES: Replace the hydraulic unit (integrated with ABS-ECU). Then go to Step 4.
NO: Replace the combination meter assembly. Then go to Step 4.

STEP 4. Retest the system
Q: Turn the ignition switch to the "ON" position. Do the ABS warning light illuminate for three seconds, and then go out after the engine starts?
YES: The procedure is complete.
NO: Return to Step 1.