B1425

DTC B1425 (2-1): OnStar Control Unit Lost Communication with SRS Unit (collision detection system line)

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 B1425 (2-1) 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.

Is DTC B1032 also indicated?

YES - Go to step 5.

NO - Go to step 6.

5. Check the SRS indicator.

Does the SRS indicator come on and stay on?

YES - Go to SRS troubleshooting.

NO - Go to step 11.

6. Turn the ignition switch OFF.
7. Disconnect OnStar control unit connector A (22P).
8. Disconnect SRS unit connector A (28P).




9. Connect SRS unit connector A (28P) terminal No. 21 to body ground with a jumper wire.




10. Check for continuity between OnStar control unit connector A (22P) terminal No. 14 and body ground.

Is there continuity?

YES - Replace the OnStar control unit.

NO - Repair an open in the wire.

11. Turn the ignition switch OFF.
12. Disconnect OnStar control unit connector A (22P).
13. Disconnect driver's under-dash fuse/relay box connector P (30P).




14. Check for continuity between OnStar control unit connector A (22P) terminal No. 14 and body ground.

Is there continuity?

YES - Repair a short to ground in the wire.

NO - Go to step 15.

15. Turn the ignition switch ON (II).




16. Measure the voltage between OnStar control unit connector A (22P) terminal No. 14 and body ground.

Is there voltage?

YES - Repair a short to power in the wire.

NO - Go to step 17

17. Turn the ignition switch OFF.
18. Disconnect SRS unit connector A (28P).




19. Connect SRS unit connector A (28P) terminal No. 21 and body ground with a jumper wire.




20. Check for continuity between OnStar control unit connector A (22P) terminal No. 14 and body ground.

Is there continuity?

YES - Go to step 21.

NO - Repair an open in the wire.

21. Remove the jumper wire from the SRS unit connector.




22. Check for continuity between driver's under-dash fuse/relay box connector P (30P) terminal No. 21 and SRS unit connector A (28P) terminal No. 21.

Is there continuity?

YES - Replace the SRS unit.

NO - Repair an open in the wire.