DTC Troubleshooting

DTC Troubleshooting: P0118, P0118

DTC P0118:

ECT Sensor 1 Circuit High Voltage

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. Check ECT SENSOR 1 in the DATA LIST with the HDS.

Is about -40 °F (-40 °C) or less, or 4.92 V or more indicated?

YES -

Go to step 3.

NO -

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at ECT sensor 1 and the ECM/PCM.�

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

4. Disconnect the ECT sensor 1 2P connector.

5. Connect ECT sensor 1 2P connector terminals No. 1 and No. 2 with a jumper wire.





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

7. Check ECT SENSOR 1 in the DATA LIST with the HDS.

Is about -40 °F (-40 °C) or less, or 4.92 V or more indicated?

YES -

Go to step 8.

NO -

Go to step 18.

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

9. Remove the jumper wire from the ECT sensor 1 2P connector.

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

11. Measure the voltage between ECT sensor 1 2P connector terminal No. 1 and body ground.





Is there about 5 V?

YES -

Go to step 12.

NO -

Go to step 17.

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

13. Jump the SCS line with the HDS.

14. Disconnect ECM/PCM connector A (31P).

15. Connect ECT sensor 1 2P connector terminal No. 2 to body ground with a jumper wire.






16. Check for continuity between ECM/PCM connector terminal A23 and body ground.





Is there continuity?

YES -

Go to step 26.

NO -

Repair open in the wire between the ECM/PCM(A23) and ECT sensor 1, then go to step 20.

17. Measure the voltage between ECM/PCM connector terminal B8 and body ground.





Is there about 5 V?

YES -

Repair open in the wire between the ECM/PCM (B8) and ECT sensor 1, then go to step 20.

NO -

Go to step 25.

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

19. Replace ECT sensor 1 ECT Sensor 1 Replacement.

20. Reconnect all connectors.

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

22. Reset the ECM/PCM with the HDS.

23. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.

24. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0118 indicated?

YES -

Check for poor connections or loose terminals at ECT sensor 1 and the ECM/PCM, then go to step 1.

NO -

Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�

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

26. Reconnect all connectors.

27. Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM.

28. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0118 indicated?

YES -

Check for poor connections or loose terminals at ECT sensor 1 and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then recheck. If the ECM/PCM was substituted, go to step 1.

NO -

If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM ECM/PCM Replacement (A/T). If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�