ENGINE (DIAGNOSTICS)(H4DO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0117 ENGINE COOLANT TEMPERATURE CIRCUIT LOW

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

• Hard to start

• Improper idling

• Poor driving performance

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK CURRENT DATA.

1) Start the engine.

2) Read the data of engine coolant temperature sensor signal using Subaru Select Monitor or general scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to “READ CURRENT DATA FOR ENGINE”.

• General scan tool

For detailed operation procedures, refer to the general scan tool operation manual.

Is the engine coolant temperature 150°C (302°F) or higher?

Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the fault condition, and reperform the check.

NOTE:

In this case, there may be a temporary connector contact failure.

2.CHECK HARNESS BETWEEN ECM AND ENGINE COOLANT TEMPERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM and engine coolant temperature sensor.

3) Measure the resistance between ECM and chassis ground.

Connector & terminal

(B137) No. 11 — Chassis ground:

Is the resistance 1 MΩ or more?

Replace the engine coolant temperature sensor.

Repair the ground short circuit of the harness between the ECM and engine coolant temperature sensor.