B1428

DTC B1428 (2-3): GPS Antenna Circuit Malfunction

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instruction 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 B1428 (2-3) 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 OnStar control unit connector C (2P).
6. Disconnect the GPS/CELLULAR PHONE antenna 2P connector.




7. Check for continuity between GPS/CELLULAR PHONE antenna 2P connector terminal No. 1 and OnStar control unit connector C (2P) terminal No. 1.

Is there continuity?

YES - Go to step 8.

NO - Repair an open in the wire.




8. Check for continuity between OnStar control unit connector C (2P) terminal No. 1 and body ground.

Is there continuity?

YES - Replace the GPS/CELLULAR PHONE antenna feeder.

NO - Go to step 9.




9. Check for continuity between the core and the outside of the feeder antenna at OnStar control unit connector C (2P) terminal No. 1.

Is there continuity?

YES - Replace the GPS/CELLULAR PHONE antenna feeder.

NO - Go to step 10.

10. Reconnect OnStar control unit connector C (2P).




11. Measure voltage between the core and the outside of the feeder antenna at GPS/CELLULAR PHONE connector (2P) terminal No. 1.

Is there about 5 V?

YES - Substitute a known-good GPS/CELLULAR PHONE antenna and recheck. If DTC B1428 (2-3) is indicated again, replace the OnStar control unit.

NO - Replace the OnStar control unit.