DTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Input
- Connect scan tool to Data Link Connector (DLC). Turn ignition on. Select ECT sensor parameter on scan tool. If scan tool displays less than -40°F (-40°C), go to next step. If scan tool displays 176-194°F (80-90°C) at normal operating temperature, check for an intermittent problem. See TESTS W/O CODES article.
- Disconnect ECT sensor harness connector. Using a fused jumper wire, connect ECT sensor harness connector terminals together. If scan tool display increases to 279°F (138°C) or greater, check for poor ECT sensor connection. Repair as necessary. If connection is okay, replace ECT sensor and retest system. If scan tool display is not as specified, remove jumper wire. If equipped with 3-speed automatic or manual transmission, go to next step. If equipped with 4-speed automatic transmission, go to step 4).
- Connect a fused jumper wire (backprobe) between terminal No. 4 (Red/Yellow wire) at 16-pin PCM harness connector, and terminal No. 15 (Gray/Yellow wire; Brown wire on some models) at 26-pin PCM harness connector. If scan tool displays 279°F (138°C) or greater, go to step 5). If scan tool display is not as specified, check for poor PCM harness connections. Repair as necessary. If connections are okay, replace PCM and retest system.
- Connect a fused jumper wire (backprobe) between terminals No. 11 (Gray/Yellow wire; Brown wire on some models) and No. 21 (Red/Yellow wire) at 22-pin PCM harness connector. If scan tool displays 279°F (138°C) or greater, go to next step. If scan tool display is not as specified, check for poor PCM harness connections. Repair as necessary. If connections are okay, replace PCM and retest system.
- Check for an open in Red/Yellow wire or Gray/Yellow wire (Brown wire on some models) between IAT sensor and PCM. Repair as necessary. If wires are okay, replace PCM and retest system.