U1501

U1501-IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM ECM/PCM

For a complete wiring diagram, refer to the wiring information Electrical Diagrams.

- When Monitored:

Continuously, with ignition on.

- Set Condition:

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






1. VERIFY THE DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE

1. Turn the ignition on.
2. With the scan tool, read and record ABS DTCs.
3. With the scan tool, read and record Environmental Data to help identify the conditions in which the DTC was set.
4. With the scan tool, erase ABS DTCs.
5. Cycle the ignition switch.
6. 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.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)s

1. 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

- Go to and perform the appropriate diagnostic procedure.

No

- Go To 3

3. CHECK IF ECM OR PCM DTCs ARE PRESENT

1. With the scan tool, read ECM or PCM DTCs.

Are any DTCs present?

Yes

- Testing and Inspection for gas engine applications.

No

- Go To 4

4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCs

1. 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 the appropriate POWERTRAIN VERIFICATION TEST. Powertrain Verification Test for gas engine applications.

No

- Using the schematics as a guide, check the Anti-Lock Brake 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 Brake Module.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.