B1178

DTC B1178: F-CAN Communication Line Error

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A.

1. Clear the DTCs with the HDS.
2. Turn the ignition switch OFF, and then back ON (II).
3. Start and run the engine for at least 5 seconds then turn the engine OFF.
4. Check for DTCs with the HDS.

Is DTC B1178 indicated?

YES - Go to step 5.

NO - Intermittent failure, the F-CAN communication line is OK at this time. Check for DTCs in the PCM with the HDS. If F-CAN DTCs are present, check for loose or poor connections at the gauge control module and the PCM. If the connections are good, check the battery condition and the charging system, then clear all DTCs.

5. Disconnect the gauge control module connectors, then reconnect them.
6. Check for DTCs with the HDS.

Is DTC B1178 still indicated?

YES - Go to step 7.

NO - Intermittent failure. The F-CAN communication line is OK at this time. Check for DTCs in the PCM with the HDS. If F-CAN DTCs are present, check for loose or poor connections at the gauge control module and the PCM. If the connections are good, check the battery condition and the charging system;

7. Check for DTCs in the PCM with the HDS.

Are any DTCs indicated?

YES - Go to the indicated PCM DTCs troubleshooting.

NO - Go to step 8.

8. Do the Gauge Control Module Input Test. Component Tests and General Diagnostics

Are all inputs OK?

YES - Go to step 9.

NO - Repair the faulty input, then recheck the DTCs.

9. Substitute a known-good gauge control module.
10. Clear the DTCs with the HDS.
11. Turn the ignition switch OFF, and then back ON (II).
12. Start and run the engine for at least 5 seconds then turn the engine OFF.
13. Check for DTCs with the HDS.

Is DTC B1178 indicated?

YES - Substitute a known-good PCM and retest. If the symptom/indication goes away, replace the original PCM.

NO - The original gauge control module is faulty; replace it.