DTC P0197 Engine Oil Temperature Sensor Low: Notes

DTC DETECTING CONDITION: 

Immediately at fault recognition

TROUBLE SYMPTOM: 

• Hard to start
• Improper idling
• Poor driving performance

WIRING DIAGRAM: 

• Engine Electrical System NON-TURBO MODEL (WITHOUT PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System >  NON-TURBO MODEL (WITHOUT PUSH BUTTON START)  .
• Engine Electrical System NON-TURBO MODEL (WITH PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System >  NON-TURBO MODEL (WITH PUSH BUTTON START)  .

1. CHECK CURRENT DATA  .
   1. Start the engine.
   2. Using the Subaru Select Monitor, read the value in [Oil Temperature].
   NOTE: For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Ref. to ENGINE (DIAGNOSTICS) (H4DO) >  Subaru Select Monitor   .

   Is the value of [Oil Temperature] 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.
2. CHECK HARNESS BETWEEN ECM AND ENGINE OIL TEMPERATURE SENSOR CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connectors from the ECM and engine oil temperature sensor.
   3. Measure the resistance between ECM connector and chassis ground.

      Connector & terminal 

      (B134) No. 20 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes: Replace the engine oil temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO) >  ENGINE OIL TEMPERATURE SENSOR  .

   No: Repair the short circuit to ground in the harness between the ECM connector and engine oil temperature sensor connector.