DTC P0117: Engine Coolant Temperature Sensor 1 Circuit Low: Notes
DTC detecting condition:
Immediately at fault recognition
Trouble symptom:
- Hard to start
- Improper idling
- Poor driving performance
CAUTION:
Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD
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NOTE:
After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE
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Wiring diagram:
Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .
- CHECK DATA MONITOR.
- Start the engine.
- Using the Subaru Select Monitor, read the value in [Coolant Temp.].NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Is the value of [Coolant Temp.] 150°C (302°F) or more?
Yes : Go to 2.
No : Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.
NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause. - CHECK HARNESS BETWEEN ECM AND ENGINE COOLANT TEMPERATURE SENSOR CONNECTOR (SHORT CIRCUIT TO GROUND).
- Turn the ignition switch to OFF.
- Disconnect the connector from ECM.
- Disconnect the connectors from the engine coolant temperature sensor.
- Measure the resistance between the ECM connector and engine ground.
Connector and terminal.
(E159) No. 15 - Engine ground:
Is the resistance 1 MΩ or more?
Yes : Replace the engine coolant temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE COOLANT TEMPERATURE SENSOR .
No : Repair the short circuit to ground in harness between ECM connector and engine coolant temperature sensor connector.