U1004

U1004-CAN C BUS TRANSMIT PERFORMANCE

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
Continuously while the system is active and there are no ECM system voltage DTCs present.

- Set Condition:
The ECM is reporting an error condition when attempting to transmit a CAN bus message.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. ACTIVE DTC
NOTE: Diagnose all CAN B and C communication DTCs before continuing.

Ignition on, engine not running.
With a scan tool, view DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.

2. COMMUNICATION DTCS PRESENT
With a scan tool check for any other communication DTCs present in other modules on the CAN C bus.
Are there any CAN C bus DTCs active at this time?

Yes

- Refer to Communications Test for this DTC and/or Manufacturer Code Charts for additional vehicle communication diagnostic procedures.

No

- Replace and program the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests