DTC Troubleshooting: U0028 (107-1)

DTC U0028:  F-CAN Communication Circuit Error (F-CAN Bus OFF)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.

1.Clear the DTC with the HDS.

2.Turn the ignition switch ON (II).

3.Check whether the DTC U0028 or U0155 is indicated in the DTCs/Freeze Data in PGM FI Mode Menu with the HDS.

Is DTC U0028 or U0155 indicated in the PGM FI system?


YES - Troubleshoot for DTC U0028 or U0155 in the PGM-FI System.


NO - Go to 4.


4.Check whether the DTC U0028 is indicated in the DTCs/Freeze Data in A/T Mode Menu with the HDS.

Is DTC U0028 indicated?


YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original  PCM.n


NO - Intermittent failure, the system is OK at this time.n