DTC P0118 - Engine Coolant Temp. (ECT) Circuit High Input

NOTE: If DTC P0108, P0113, P0118, P0123 and/or P0450 are set together, Light Green/Black wire (sensor ground) may be open.

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Observe engine coolant temperature displayed on scan tool. If display reads -40°F (-40°C), go to next step. If display reading is not as specified, check for an intermittent problem. See TESTS W/O CODES article.
Turn ignition off. Disconnect ECT sensor harness connector located near coolant outlet. Turn ignition on. Using a voltmeter, measure voltage between ground and Light Gray/White wire of ECT sensor harness connector. If reading is 4-6 volts, go to next step. If reading is greater than 4-6 volts, check Gray/White wire for short to battery power. Repair as necessary. Retest system.
Turn ignition off. Disconnect PCM connector "B". Using an ohmmeter, check for continuity between Light Green/Black wire of ECT sensor harness connector and PCM harness connector "B", terminal No. 9. If continuity exists, go to next step. If continuity does not exist, check Light Green/Black wire for an open or poor connection. Repair as necessary. Retest system. 4) Reconnect PCM connector. Turn ignition on. Using a fused jumper wire, jumper ECT sensor terminals of harness connector together. If display on scan tool reads 246°F (119°C), replace ECT sensor. If display reading is not as specified, replace PCM. Retest system.