U1503

U1503-IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM FCM





For the Anti-Lock Brake System circuit diagram. Refer to SCHEMATICS AND DIAGRAMS.

When Monitored
Continuously with the ignition on.

Set Condition
When the Anti-Lock Brake Module detects an incorrect CAN message from the Front Control Module (FCM).

Possible Causes
- FCM CAN BUS DTCS
- ANTI-LOCK BRAKE MODULE

Diagnostic Test
1. CHECK IF FCM CAN BUS DTC'S ARE PRESENT





With the scan tool, read FCM DTCs.

Are there any FCM CAN BUS DTCs present?
Yes >> Refer to 8-ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING and diagnose the appropriate symptom.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Using the schematics as a guide, check the Anti-Lock Brake Module pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the Anti-Lock Brake Module per the Service Information.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test