DTC Troubleshooting

DTC Troubleshooting: P1658

DTC P1658: ETCS Control Relay ON Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview

1. Turn the ignition switch to ON (II).

2. Do the ETCS TEST in the INSPECTION MENU with the HDS.

Is the RELAY circuit OK?
YES - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the under-hood fuse/relay box (ETCS control relay) and the PCM.

NO - Go to step 3.


3. Turn the ignition switch to LOCK (0).

4. Test the ETCS control relay in the under-hood fuse/relay box Power Relay Test.

ETCS control relay OK?
YES - Go to step 5.

NO - Replace the relay control module (under-hood fuse/relay box), Under-Hood Fuse/Relay Box Removal and Installation then go to step 14.


5. Jump the SCS line with the HDS.

6. Disconnect PCM connector A (49P).

7. Disconnect the under-hood fuse/relay box connector E (14P).

8. Check for continuity between PCM connector terminal A29 and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (A29) and the under-hood fuse/relay box (ETCS control relay), then go to step 14.

NO - Go to step 9.






9. Disconnect PCM connector C (49P).

10. Disconnect the under-hood fuse/relay box connector H (9P).

11. Turn the ignition switch to ON (II).

12. Measure the voltage between PCM connector terminal C4 and body ground.

Is there battery voltage?
YES - Repair short to power in the wire between the PCM (C4) and the under-hood fuse/relay box (ETCS control relay), then go to step 13.

NO - Go to step 19.






13. Turn the ignition switch to LOCK (0).

14. Reconnect all connectors.

15. Turn the ignition switch to ON (II).

16. Reset the PCM with the HDS.

17. Do the PCM idle learn procedure. PCM Idle Learn Procedure

18. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1658 indicated?
YES - Check for poor connections or loose terminals at the under-hood fuse/relay box (ETCS control relay) and the PCM, then go to step 1.

NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


19. Turn the ignition switch to LOCK (0).

20. Reconnect all connectors.

21. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Initial Inspection and Diagnostic Overview

22. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1658 indicated?
YES - Check for poor connections or loose terminals at the under-hood fuse/relay box (ETCS control relay) and the PCM. If the PCM was updated, substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the PCM was substituted, go to step 1.

NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.