DTC P0459 Evaporative Emission Control System Purge Control Valve Circuit High

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

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P0459 EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT HIGH , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Erroneous idling

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 P0459 Circuit

Courtesy of SUBARU OF AMERICA, INC.

DTC P0459 DIAGNOSIS

Step	Check	Yes	No
1. CHECK OUTPUT SIGNAL FROM ECM. Turn the ignition switch to OFF. Connect the test mode connector at the lower portion of instrument panel (on the driver's side). Turn the ignition switch to ON. While operating the purge control solenoid valve, measure voltage between ECM and chassis ground. NOTE: Purge control solenoid valve operation can be executed using Subaru Select Monitor. For procedure, refer to COMPULSORY VALVE OPERATION CHECK MODE . Connector & terminal (B134) No. 14 (+) - Chassis ground (-):	Is the voltage 0 - 10 V?	Go to step 2.	Even if malfunction indicator light lights up, the circuit has returned to a normal condition at this time. In this case, repair poor contact in ECM connector.
2. CHECK OUTPUT SIGNAL FROM ECM. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 14 (+) - Chassis ground (-):	Is the voltage more than 10 V?	Go to step 4.	Go to step 3.
3. CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	Repair poor contact in ECM connector.	Replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM)
4. CHECK HARNESS BETWEEN PURGE CONTROL SOLENOID VALVE AND ECM CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from purge control solenoid valve. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 14 (+) - Chassis ground (-):	Is the voltage more than 10 V?	Repair battery short circuit in harness between ECM and purge control solenoid valve connector. After repair, replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . >	Go to step 5.
5. CHECK PURGE CONTROL SOLENOID VALVE. Turn the ignition switch to OFF. Measure the resistance between purge control solenoid valve terminals. Terminals No. 1 - No. 2:	Is the resistance less than 1 Ω?	Replace the purge control solenoid valve< Ref. to PURGE CONTROL SOLENOID VALVE .> and ECM < Ref. to ENGINE CONTROL MODULE (ECM) . >	Go to step 6.
6. CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	Repair poor contact in ECM connector.	Replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . >