Inspection Procedure 4
INSPECTION PROCEDURE 3: When the Ignition Key is Turned to "ON" (Engine Stopped), the BRAKE/ABS Warning Light does not Illuminate. INSPECTION PROCEDURE 4: The BRAKE/ABS Warning Light Remains Illuminated after the Engine is Started.EBD and ABS Warning Light Circuit
EBD and ABS Warning Light Circuit:
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.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)
^ Damaged wiring harness or connector
^ Combination meter defect
^ Malfunction of the hydraulic unit (integrated with ABS-ECU)
DIAGNOSIS
Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (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.
Use scan tool MB991958 to diagnose the CAN bus lines.
(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.
Q: Is the check result satisfactory?
YES: Go to Step 2.
NO: Repair the CAN bus lines.
STEP 2. Using scan tool MB991958, read the combination meter 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.
Use scan tool MB991958 to check whether combination meter DTC U1102 has been set.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check whether combination meter DTC U1102 has been set.
Q: Is combination meter DTC U1102 set?
YES: Replace the hydraulic unit (integrated with ABS-ECU).
NO: Replace the combination meter.