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DTC P0118 - ECT Sensor Circuit High Input

  1. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Select ECT sensor parameter on scan tool. If display reads lower than -40°F, go to next step. If display reading is 176-194°F at normal operating temperature, check for an intermittent problem. See TESTS W/O CODES article.
  2. Disconnect ECT sensor harness connector. Using a fused jumper wire, connect ECT sensor harness connector terminals together. If display reading rises to 279°F or more, check for poor ECT sensor connection. If connection is okay, replace ECT sensor. Retest system. If display reading is not as specified, go to next step.
  3. Remove jumper wire from sensor connector. Using a fused jumper wire, connect (backprobe) PCM harness connector "A", terminal No. 4 (Red/Yellow wire) and connector "B", terminal No. 15 (Gray/Yellow or Black wire) together. See Figure . If display reading is 279°F or more, go to next step. If reading is not as specified, check for poor PCM connections. If connections are okay, replace PCM. Retest system.
  4. Check for open Red/Yellow wire or Black wire between IAT sensor and PCM. If wires are okay, replace PCM. Retest system.
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