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 (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch OFF, and then back ON (II).
Start and run the engine for at least 5 seconds then turn the engine off.
Check for DTCs with the HDS.
Is DTC B1178 indicated?
1. YES - Go to step 5.
2. 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 (see BATTERY TEST ) and the charging system, then clear all DTCs.
Check for DTCs in the PCM with the HDS.
Are any DTCs indicated?
1. YES - Go to the indicated PCM DTC's troubleshooting.
2. NO - Go to step 6.
Do the gauge control module input test (see GAUGE CONTROL MODULE INPUT TEST ).
Are all inputs OK?
1. YES - Go to step 7.
2. NO - Repair the faulty input, then recheck the DTCs.
Substitute a known-good gauge control module.
Clear the DTCs with the HDS.
Turn the ignition switch OFF, and then back ON (II).
Start and run the engine for at least 5 seconds then turn the engine off.
Check for DTCs with the HDS.
Is DTC B1178 indicated?
1. YES - Substitute a known-good PCM.
2. NO - The original gauge control module is faulty; replace it (see GAUGE CONTROL MODULE REPLACEMENT ).