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DTC B1168: Gauge Control Module Lost Communication with ECM/PCM (Engine Messages); DTC B1169: Gauge Control Module Lost Communication with the PCM (A/T Messages); DTC B1170: Gauge Control Module Lost Communication with the ABS/VSA modulator-Control Unit (ABS/VSA message); DTC B1178: F-CAN Communication Line Error; DTC B1187: Gauge Control Module Lost Communication with the SRS Unit (SRS Message)

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 using 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 B1168, B1169, B1170, B1178, and/or B1187 indicated?

YES -Go to step 5.

NO -Intermittent failure, the F-CAN communication line is OK at this time. Check for loose or poor connections. If the connections are good, check the battery condition (see BATTERY ), and the charging system.
Check for DTCs in the ECM/PCM or ABS/VSA.
Are any DTCs indicated?

YES -Troubleshoot the ECM/PCM or ABS/VSA.

NO -Go to step 6.
Do the Gauge Control Module Input Test (see GAUGE CONTROL MODULE (TACH) INPUT TEST ).
Are all inputs OK?

YES -Go to step 7.

NO -Repair the faulty input then recheck for DTCs.
Substitute a known-good gauge control module (tach).
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 B1168, B1169, B1170, B1178, and/or B1187 indicated?

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

NO -The original gauge control module (tach) is faulty; replace the GAUGE CONTROL MODULE (TACH) (see GAUGE CONTROL MODULE REPLACEMENT ).