DTC Troubleshooting

DTC Troubleshooting: 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), or press the engine start/stop button to select the ON mode.

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 PCM.


3. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

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), or press the engine start/stop button to select the ON mode.






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 20.


8. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

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

10. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

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 16.






12. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

13. Jump the SCS line with the HDS.

14. Disconnect PCM connector C (49P).

15. Check for continuity between PCM connector terminal C16 and ECT sensor 1 2P connector terminal No. 2.

Is there continuity?
YES - Go to step 27.

NO - Repair open in the wire between the PCM (C16) and ECT sensor 1, then go to step 22.






16. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

17. Jump the SCS line with the HDS.

18. Disconnect PCM connector C (49P).

19. Check for continuity between PCM connector terminal C32 and ECT sensor 1 2P connector terminal No. 1.

Is there continuity?
YES - Go to step 27.

NO - Repair open in the wire between the PCM (C32) and ECT sensor 1, then go to step 22.






20. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

21. Replace ECT sensor 1. ECT Sensor 1 Replacement

22. Reconnect all connectors.

23. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

24. Reset the PCM with the HDS.

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

26. 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 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.


27. Reconnect all connectors.

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

29. 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 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. PCM Replacement If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.