IMA System (MCM)

DTC Troubleshooting: U0028 (107)

DTC U0028 (107):

F-CAN Malfunction (BUS-OFF (MCM))

NOTE:

- To verify this is the appropriate troubleshooting procedure, jump the SCS with the HDS and read the flash code, or change the HDS setup to show HM codes and read the HM code.
- Before you troubleshoot, record all freeze data, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS Initial Inspection and Diagnostic Overview.

3. Check for Pending or Confirmed DTCs in the IMA SYSTEM with the HDS.

Is DTC U0028 (107) indicated?

YES -

Go to step 4.

NO -

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the PCM and the MCM.�

4. Check for Pending or Confirmed DTCs in the IMA SYSTEM with the HDS.

Is DTC U0028 (108) indicated?

YES -

Go to step 5.

NO -

Go to step 10.

5. Check for Pending or Confirmed DTCs in the PGM-FI SYSTEM with the HDS.

Is DTC U0028 indicated?

YES -

Do the troubleshooting for DTC U0028 U0028.

NO -

Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM Initial Inspection and Diagnostic Overview, then recheck. If the symptom/indication goes away with an updated PCM, go to step 6. If the symptom/indication goes away with a known-good PCM, replace the original PCM Service and Repair, then go to step 6.

6. Turn the ignition switch to ON (II).

7. Clear the DTC with the HDS Initial Inspection and Diagnostic Overview.

8. Check for Pending or Confirmed DTCs in the IMA SYSTEM with the HDS.

Is DTC U0028 (107) indicated?

YES -

Check for poor connections or loose terminals at the PCM, the BCM module, and the MCM, then go to step 1.

NO -

Go to step 9.

9. Monitor the OBD STATUS for DTC U0028 (107) in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES -

Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 8, go to the indicated DTC's troubleshooting.�

NO -

If the screen indicates FAILED, check for poor connections or loose terminals at the PCM, the BCM module, and the MCM, then go to step 1. If the screen indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.

10. Update the MCM if it does not have the latest software Testing and Inspection, or substitute a known-good MCM Initial Inspection and Diagnostic Overview.

11. Check for Pending or Confirmed DTCs in the IMA SYSTEM with the HDS.

Is DTC U0028 (107) indicated?

YES -

Check for poor connections or loose terminals at the PCM, the BCM module, and the MCM. If the MCM was updated, substitute a known-good MCM Initial Inspection and Diagnostic Overview, then recheck. If the MCM was substituted, go to step 1.

NO -

Go to step 12.

12. Monitor the OBD STATUS for DTC U0028 (107) in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES -

If the MCM was updated, troubleshooting is complete. If the MCM was substituted, replace the original MCM MCM Replacement. If any other Pending or Confirmed DTCs were indicated in step 11, go to the indicated DTC's troubleshooting.�

NO -

If the screen indicates FAILED, check for poor connections or loose terminals at the PCM, the BCM module, and the MCM. If the MCM was updated, substitute a known-good MCM Initial Inspection and Diagnostic Overview, then recheck. If the MCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.