The PCM sends engine/axle/tire Ids to the EBCM via class 2 serial data communications immediately after the modules are powered up.
The ignition is ON.
One or more of the Ids received by the EBCM does not correspond with a valid vehicle Id.
| • | The TRACTION OFF indicator is commanded on. | 
| • | The Traction Control is disabled for the remainder of the ignition cycle. | 
| • | Repair the condition(s) responsible for setting the DTC. | 
| • | Use a scan tool in order to clear the DTC. | 
DTC C0279 may set due to a class 2 serial data circuit malfunction or an internal module malfunction. In either situation, diagnose other DTC(s) stored by the EBCM or PCM prior to diagnosing DTC C0279.
Action  | Yes  | No  | |
|---|---|---|---|
1  | Did you perform the ABS Diagnostic System Check?  | Go to Step 2  | Go to Diagnostic System Check  | 
2  | 
 Does the DTC set?  | Go to Step 3  | Go to Diagnostic Aids  | 
Verify that the correct PCM is installed in the vehicle. Does the vehicle have the correct PCM?  | Go to Step 4  | Go to Step 6  | |
4  | Use the scan tool in order to read the trim level calibration of the PCM. Is the trim level calibration of the PCM correct?  | Go to Diagnostic Aids  | Go to Step 5  | 
5  | Program the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, and 6.0L. Did you complete the action?  | Go to Step 7  | --  | 
6  | 
 Important: Perform the set up procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, and 6.0L. Did you complete the replacement?  | Go to Step 7  | --  | 
7  | 
 Does the DTC set?  | Go to Step 3  | System OK  |