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).
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 20.
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 the ECT sensor 1 2P connector terminal No. 2 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).
13. Jump the SCS line with the HDS.
14. Disconnect ECM/PCM connector B (44P).
15. Check for continuity between ECT sensor 1 2P connector terminal No. 1 and ECM/PCM connector terminal B33.
Is there continuity?
YES - Go to step 27.
NO - Repair open in the wire between the ECM/PCM (B33) and ECT sensor 1, then go to step 22.
16. Turn the ignition switch to LOCK (0).
17. Jump the SCS line with the HDS.
18. Disconnect ECM/PCM connector B (44P).
19. Check for continuity between ECT sensor 1 2P connector terminal No. 2 and ECM/PCM connector terminal B23.
Is there continuity?
YES - Go to step 27.
NO - Repair open in the wire between the ECM/PCM (B23) and ECT sensor 1, then go to step 22.
20. Turn the ignition switch to LOCK (0).
21. Replace ECT sensor 1. ECT Sensor 1 Replacement
22. Reconnect all connectors.
23. Turn the ignition switch to ON (II).
24. Reset the ECM/PCM with the HDS.
25. Do the ECM/PCM idle learn procedure. ECM/PCM Idle Learn Procedure (A/T)
26. Check for Temporary DTCs or 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 Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
27. Reconnect all connectors.
28. 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
29. Check for Temporary DTCs or 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, 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.