DTC Troubleshooting

DTC Troubleshooting: P0117

DTC P0117: ECT Sensor 1 Circuit Low 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 356 °F (180 °C) or more, or 0.08 V or less 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. Turn the ignition switch to ON (II).

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

Is about 356 °F (180 °C) or more, or 0.08 V or less indicated?
YES - Go to step 7.

NO - Go to step 11.


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

8. Jump the SCS line with the HDS.

9. Disconnect ECM/PCM connector B (44P).

10. Check for continuity between ECT sensor 1 2P connector terminal No. 2 and body ground.

Is there continuity?
YES - Repair short in the wire between ECT sensor 1 and the ECM/PCM (B23), then go to step 13.

NO - Go to step 18.






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

12. Replace ECT sensor 1. ECT Sensor 1 Replacement

13. Reconnect all connectors.

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

15. Reset the ECM/PCM with the HDS.

16. Do the ECM/PCM idle learn procedure. ECM/PCM Idle Learn Procedure (A/T)

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

Is DTC P0117 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 Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


18. Reconnect all connectors.

19. Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM. Initial Inspection and Diagnostic Overview

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

Is DTC P0117 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, Initial Inspection and Diagnostic Overview 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. Service and Repair If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.