U1501

U1501-IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM ECM/PCM

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
Continuously, with ignition on.

- Set Condition:
If the Anti-Lock Brakes Module detects bus messages from the Engine Control Module (ECM) or Powertrain Control Module (PCM) are of improper data length.





Diagnostic Test

1. VERIFY DTC IS ACTIVE
Turn the ignition on.
With the scan tool, read and record ABS DTCs.
With the scan tool, read and record Environmental Data (EV Data).
With the scan tool, erase ABS DTCs.
Cycle the ignition switch.
With the scan tool, read ABS DTCs.
Does this DTC reset?

Yes

- Go to 2

No

- The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
- Refer to the ABS-INTERMITTENT CONDITION TEST. ABS Intermittent Condition Test

2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCs
With the scan tool, read all active DTCs from all CAN C Bus modules.

NOTE: Check for CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

Does the scan tool display any active DTCs related to the conditions listed above?

Yes

- Diagnose and repair the DTC(s).

No

- Go to 3

3. CHECK IF ECM OR PCM DTCs ARE PRESENT
With the scan tool, read ECM or PCM DTCs.
Are any DTCs present?

Yes

- Diagnose and repair the DTC(s).
- Perform ABS VERIFICATION TEST. ABS Verification Test.

No

- Go to 4

4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCs
With the scan tool, select Network View and select Advanced.
Is there more than one module with active DTCs "Logged Against" the ECM or PCM?

Yes

- Replace/update the ECM or PCM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
- Perform ABS VERIFICATION TEST. ABS Verification Test.

No

- Using the schematics as a guide, check the Anti-Lock Brakes Module pins, terminals, and connectors for corrosion, damage, and terminal push out. Pay particular attention to all Communication circuits. If no problems are found, replace the Anti-Lock Brakes Module.
- Perform ABS VERIFICATION TEST. ABS Verification Test.