B1426

DTC B1426 (2-5): OnStar Switches Circuit Malfunction

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 B1426 (2-5) indicated?

YES - Go to step 4.

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

4. Turn the ignition switch OFF.
5. Disconnect the roof console 28P connector.




6. Check for continuity between roof console 28P connector terminals No. 1 and body ground.

Is there continuity?

YES - Repair a short to ground in the wire between OnStar control unit connector B (16P) terminal No. 6 and roof console 28P connector terminal No. 1.

NO - Go to step 7.




7. Measure resistance between roof console 28P connector terminals No. 1 and No. 2.

Is there about 4 K Ohms?

YES - Go to step 8.

NO - Replace the roof console.

8. Disconnect OnStar control unit connector B (16P).




9. Connect roof console 28P connector terminals No. 1 and No. 2 to body ground with jumper wires.




10. Check for continuity between body ground and OnStar control unit connector B (16P) terminals No. 6 and No. 14 individually.

Is there continuity?

YES - Go to step 11.

NO - Repair an open in the wire.

11. Remove the jumper wire from the roof console.
12. Turn the ignition switch ON (II).




13. Measure voltage between body ground and OnStar control unit connector B (16P) terminals No. 6 and No. 14 individually.

Is there voltage?

YES - Repair a short to power in the wire.

NO - Replace the OnStar control unit.