DTC Troubleshooting: P0118 (6)
DTC P0118:
 ECT Sensor 1 Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Check the ECT SENSOR 1 in the DATA LIST with the HDS.
Is about 4.95 V or higher 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.■
  1. Turn the ignition switch OFF.
  1. Disconnect the ECT sensor 1 2P connector.
  1. Connect ECT sensor 1 2P connector terminals No. 1 and No. 2 with a jumper wire.
  1. Turn the ignition switch ON (II).
  1. Check the ECT SENSOR 1 in the DATA LIST with the HDS.
Is about 4.95 V or higher indicated?
YES -
Go to Step 8 .
NO -
Go to Step 18 .
  1. Remove the jumper wire from the ECT sensor 1 2P connector.
  1. Measure voltage between ECT sensor 1 2P connector terminal No. 2 and body ground.
Is there about 5 V?
YES -
Go to Step 10 .
NO -
Go to Step 14 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Connect ECT sensor 1 2P connector terminal No. 1 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 56 and body ground.
Is there continuity?
YES -
Go to Step 24 .
NO -
Repair open in the wire between ECT sensor 1 and ECM connector No. 1 terminal No. 56, then go to Step 20 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Connect ECT sensor 1 2P connector terminal No. 2 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 67 and body ground.
Is there continuity?
YES -
Go to Step 24 .
NO -
Repair open in the wire between ECT sensor 1 and ECM connector No. 1 terminal No. 67, then go to Step 20 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. 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, 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.■
  1. Reconnect all connectors.
  1. 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. If the ECM was updated, substitute a known-good ECM, then recheck. If the ECM was substituted, go to Step 1 .
NO -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■