DTC P0117: Engine Coolant Temperature Circuit Low Input

DTC DETECTING CONDITION:

Immediately at fault recognition
GENERAL DESCRIPTION < Ref. to DTC P0117 ENGINE COOLANT TEMPERATURE CIRCUIT LOW INPUT , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Hard to start
Erroneous idling
Poor driving performance

CAUTION: After repair or replacement of faulty parts, conduct Clear Memory Mode < Ref. to , OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to , PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM:

Fig 1: DTC P0117 - Engine Coolant Temperature Circuit Low Input - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC STEPS DTC P0117

Step	Check	Yes	No
1 CHECK CURRENT DATA. Start the engine. Read the data of engine coolant temperature sensor signal using Subaru Select Monitor or OBD-II general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to , SUBARU SELECT MONITOR . > OBD-II general scan tool For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.	Is the engine coolant temperature more than 150°C (302°F)?	Go to step 2 .	Repair poor contact. NOTE: In this case, repair the following: Poor contact in engine coolant temperature sensor Poor contact in ECM Poor contact in coupling connector Poor contact in joint connector
2 CHECK HARNESS BETWEEN ENGINE COOLANT TEMPERATURE SENSOR AND ECM CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from engine coolant temperature sensor. Turn the ignition switch to ON. Read the data of engine coolant temperature sensor signal using Subaru Select Monitor or OBD-II general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to , SUBARU SELECT MONITOR . > OBD-II general scan tool For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.	Is the engine coolant temperature less than -40°C (-40°F)?	Replace the engine coolant temperature sensor. < Ref. to ENGINE COOLANT TEMPERATURE SENSOR . >	Repair ground short circuit in harness between engine coolant temperature sensor and ECM connector.