DTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Input - Legacy & Outback 2.5L A/T
- Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE . Start engine. Using scan tool, observe engine coolant temperature signal. If temperature is less than -40°F (-40°C), go to next step. If temperature is not less than -40°F (-40°C), check for poor terminal contact in connectors between ECM and ECT sensor.
- Turn ignition off. Disconnect ECT sensor connector. Using a DVOM connected to ground, measure voltage at ECT sensor connector terminal No. 1. See Figure. If voltage is more than 10 volts, locate and repair short to voltage in wiring between ECM and ECT sensor. See WIRING DIAGRAMS article. If voltage is not more than 10 volts, go to next step.
- Turn ignition on. Using a DVOM connected to ground, measure voltage at ECT sensor connector terminal No. 1. If voltage is more than 10 volts, locate and repair short to voltage in wiring between ECM and ECT. If voltage is not more than 10 volts, go to next step.
- Using a DVOM connected to ground, measure voltage at ECT sensor connector terminal No. 1. If voltage is more than 4 volts, go to next step. If voltage is not more than 4 volts, locate and repair open in wiring and check for poor terminal contact in connectors between ECM and ECT sensor.
- Turn ignition off. Using an ohmmeter, measure resistance between ground and ECT sensor connector terminal No. 2. If resistance is less than 5 ohms, replace ECT sensor. If resistance is not less than 5 ohms, locate and repair open in wiring and check for poor terminal contact in connectors between ECM and ECT sensor. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES and VERIFICATION PROCEDURE .