B1405

DTC B1405 (3-2): OnStar Control Unit Lost Communication with Driver's MPCS Unit (Door Switch Message)

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

1. Delete the DTCs.
2. Turn the ignition switch OFF, and then back ON (II).
3. Check for DTCs.

Is DTC B1405 (3-2) indicated?

YES - Go to step 4.

NO - Intermittent failure. The system is OK at this time. Check for loose or poor connections.

4. Check for DTCs with the HDS.

Are DTCs B1014, B1064, B1181, B1613 and B1811 also indicated

YES - Go to the driver's MPCS unit input test. Driver's MPCS Unit Input Test If the driver's MPCS unit input test is OK, replace the OnStar control unit.

NO - Replace the OnStar control unit.