DTC P0458 Evaporative Emission System Purge Control Valve Circuit Low: Wiring Diagram

Engine electrical system, 2.5 L model (without push button start). See appropriate SYSTEM WIRING DIAGRAM article.
Engine electrical system, 2.5 L model (with push button start). See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Evaporative Emission System Purge Control Valve - Circuit Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK OUTPUT SIGNAL OF ECM. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 11 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 2 .	Go to step 3 .
2 CHECK FOR POOR CONTACT. Check for poor contact of ECM connector.	Is there poor contact of ECM connector?	Repair the poor contact of ECM connector.	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 open or short circuit of harness or temporary poor contact of connector may be the cause.
3 CHECK POWER SUPPLY TO PURGE CONTROL SOLENOID VALVE. Measure the voltage between purge control solenoid valve connector and engine ground. Connector & terminal (E4) No. 1 (+) - Engine ground (-):	Is the voltage 10 V or more?	Go to step 4 .	Repair the power supply circuit.
4 CHECK HARNESS BETWEEN ECM AND PURGE CONTROL SOLENOID VALVE CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from ECM and purge control solenoid valve. Measure the resistance between the purge control solenoid valve connector and engine ground. Connector & terminal (E4) No. 2 - Engine ground:	Is the resistance 1 MΩ or more?	Go to step 5 .	Repair the ground short circuit of harness between ECM and purge control solenoid valve connector.
5 CHECK HARNESS BETWEEN ECM AND PURGE CONTROL SOLENOID VALVE CONNECTOR. Measure the resistance of harness between ECM and purge control solenoid valve. Connector & terminal (B134) No. 11 - (E4) No. 2:	Is the resistance less than 1 Ω?	Go to step 6 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between ECM and purge control solenoid valve connector Poor contact of coupling connector
6 CHECK PURGE CONTROL SOLENOID VALVE. Remove the purge control solenoid valve. Measure the resistance between purge control solenoid valve terminals. Terminals No. 1 - No. 2:	Is the resistance 10 - 100 Ω?	Repair the poor contact of purge control solenoid valve connector.	Replace the purge control solenoid valve. Refer to PURGE CONTROL SOLENOID VALVE .