DTC P0198: Engine Oil Temperature Sensor High: Wiring Diagram

WARNING: This page is about a different variant/trim than selected.

Engine electrical system, 3.6 L model (without push button start). See appropriate SYSTEM WIRING DIAGRAM article.
Engine electrical system, 3.6 L model (with push button start). See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Engine Oil Temperature Sensor - Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK CURRENT DATA. Start the engine. Read the value of «Oil Temperature» using Subaru Select Monitor. NOTE: For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Refer to SUBARU SELECT MONITOR .	Is the value of «Oil Temperature » less than -40°C (-40°F)?	Go to step 2 .	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 FOR POOR CONTACT. Check for poor contact between the ECM and engine oil temperature sensor connectors.	Is there poor contact of the ECM or engine oil temperature sensor connectors?	Repair the poor contact of ECM or engine oil temperature sensor connector.	Go to step 3 .
3 CHECK HARNESS BETWEEN ECM AND ENGINE OIL TEMPERATURE SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from the ECM and engine oil temperature sensor. Measure the resistance of the harness between the ECM and engine oil temperature sensor connector. Connector & terminal (B134) No. 29 - (E75) No. 1: (B137) No. 21 - (E75) No. 2:	Is the resistance less than 1 Ω?	Go to step 4 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between ECM and engine oil temperature sensor connector Poor contact of coupling connector
4 CHECK HARNESS BETWEEN ECM AND ENGINE OIL TEMPERATURE SENSOR CONNECTOR. Connect all connectors. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B137) No. 21 (+) - Chassis ground (-):	Is the voltage 5 V or more?	Repair the short circuit to power in harness between ECM and engine oil temperature sensor connector.	Replace the engine oil temperature sensor. Refer to OIL TEMPERATURE SENSOR .