U1004-CAN C BUS TRANSMIT PERFORMANCE

For a complete wiring diagram Refer to Section 8W

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.

Possible Causes

INTERMITTENT DTC

CAN BUS ERROR CONDITION

ENGINE CONTROL MODULE (ECM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

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. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

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 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for additional vehicle communication diagnostic procedures.

No

Replace and program the Engine Control Module (ECM) in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)