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Home >> Subaru >> 2017 >> WRX Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (Diagnostics) (P0171 To P0685) (2.0L) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P04AD EVAP System (CPC) Purge Control Valve "B" Circuit High >> Notes

DTC P04AD EVAP System (CPC) Purge Control Valve "B" Circuit High: Notes

DTC DETECTING CONDITION: 

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM: 

Improper idling

CAUTION:
  • After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to OPERATION , Clear Memory Mode.>, and Inspection Mode <Ref. to PROCEDURE , Inspection Mode.>.
  • Use the check board when measuring the ECM terminal voltage and resistance.

WIRING DIAGRAM: 

Engine Electrical System <Ref. to WIRING DIAGRAM , Engine Electrical System.>

Fig 1: EVAP System Purge Control Valve A Circuit Wiring Diagram (Low)
G11577188Courtesy of SUBARU OF AMERICA, INC.
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND PURGE CONTROL SOLENOID VALVE 2 CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from ECM.
  3. Disconnect the connector from purge control solenoid valve 2.
  4. Turn the ignition switch to ON.
  5. Measure the voltage between ECM connector and chassis ground.

Connector & terminal 
(E159) No. 12 (+) - Chassis ground (-): 
Is the voltage 10 V or more? Repair the short circuit to power in harness between ECM connector and purge control solenoid valve 2 connector. Go to step .
2 CHECK PURGE CONTROL SOLENOID VALVE 2. 
  1. Turn the ignition switch to OFF.
  2. Measure the resistance between purge control solenoid valve 2 terminals.

Terminals 
No. 1 - No. 2: 
Is the resistance less than 1 Ω? Replace the purge control solenoid valve 2. <Ref. to Purge Control Solenoid Valve .> Repair the poor contact of ECM connector.