DTC P0117: Engine Coolant Temperature (ECT) Sensor Circuit High Input
- Turn ignition off. Connect scan tool. Start engine. Observe coolant temperature display. If displayed value is less than -40°F (-40°C), go to next step. If displayed value is -40°F (-40°C) or more, check for poor contact in connectors between ECM and ECT sensor connectors.
- Turn ignition off. Disconnect ECT sensor connector. Using a DVOM connected to ground, measure voltage at ECT sensor connector terminal No. 1. See Fig 1. If voltage is more than 10 volts, repair short to voltage in wiring between ECM and ECT sensor connectors. See appropriate wiring diagram in WIRING DIAGRAMS
article. If voltage is 10 volts or less, go to next step.
Courtesy of SUBARU OF AMERICA, INC.
- Turn ignition on. Measure voltage between ground and ECT sensor connector terminal No. 1. If voltage is more than 10 volts, repair short to voltage in wiring between ECM and ECT connectors. If voltage is 10 volts or less, go to next step.
- Measure voltage between ground and ECT sensor connector terminal No. 1. If voltage is more than 4 volts, go to next step. If voltage is 4 volts or less, repair open in wiring or poor contact in connectors between ECM and ECT sensor connectors.
- 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 5 ohms or more, repair open in wiring or poor connection between ECM and ECT sensor connectors.