DTC P1516 - ISC Solenoid Valve Signal #4 Circuit Malfunction (Low Input) -

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

DTC DETECTING CONDITION:
- Detected simultaneously at occurrence of malfunction.
TROUBLE SYMPTOM:
- Erroneous idling
- Engine stalls.
- Engine breathing
CAUTION: After repair or replacement of malfunctioning parts, conduct Clear Memory Mode < Ref. to OPERATION , CLEAR MEMORY MODE > and INSPECTION MODE < Ref. to OPERATION , INSPECTION MODE. >
WIRING DIAGRAM:

Fig 1: ISC Solenoid Valve Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK POWER SUPPLY TO IDLE AIR CONTROL SOLENOID VALVE. Turn ignition switch to OFF. Disconnect connector from idle air control solenoid valve. Turn ignition switch to ON. Measure voltage between idle air control solenoid valve connector and engine ground. Connector & terminal (E7) No. 2 (+) - Engine ground (-): (E7) No. 5 (+) - Engine ground (-):	Is the measured value more than 10 V?	Go to step 2.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between idle air control solenoid valve and main relay connector Poor contact in coupling connector
2 CHECK POWER SUPPLY TO IDLE AIR CONTROL SOLENOID VALVE. Measure voltage between idle air control solenoid valve connector and engine ground.	Is the measured value more than 10 V?	Go to step 3.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between idle air control solenoid valve and main relay connector Poor contact in coupling connector
3 CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR. Turn ignition switch to OFF. Measure resistance between ECM and idle air control solenoid valve connector. Connector & terminal DTC P1510; (B134) No. 20 - (E7) No. 4: DTC P1512; (B134) No. 6 - (E7) No. 1: DTC P1514; (B134) No. 5 - (E7) No. 6: DTC P1516; (B134) No. 19 - (E7) No. 3:	Is the measured value less than 1 Ω?	Go to step 4.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between ECM and idle air control solenoid valve connector Poor contact in coupling connector
4 CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR. Disconnect connector from ECM. Measure resistance between ECM connector and chassis ground. Connector & terminal DTC P1510; (B134) No. 20 - Chassis ground: DTC P1512; (B134) No. 6 - Chassis ground: DTC P1514; (B134) No. 5 - Chassis ground: DTC P1516; (B134) No. 19 - Chassis ground:	Is the measured value more than 1 Ω?	Repair ground short circuit in harness between ECM and idle air control solenoid valve connector.	Go to step 5.
5 CHECK POOR CONTACT. Check poor contact in ECM connector and idle air control solenoid valve connector.	Is there poor contact in ECM connector or idle air control solenoid valve connector?	Repair poor contact in ECM connector or idle air control solenoid valve connector.	Replace idle air control solenoid valve. < Ref. to IDLE AIR CONTROL SOLENOID VALVE . >