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HOMESERVICE MANUALSSUBARU2005OUTBACK I, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - ENGINE (DIAGNOSTICS) (H4SO)DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)DTC P0459 EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT HIGH
2005 Subaru Outback i, Standard

DTC P0459 Evaporative Emission Control System Purge Control Valve Circuit High

2005 Subaru Outback i, StandardSECTION DTC P0459 Evaporative Emission Control System Purge Control Valve Circuit High

DTC DETECTING CONDITION: 

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
G03828492Courtesy of SUBARU OF AMERICA, INC.
DTC P0459 DIAGNOSIS

Step Check Yes No
1. CHECK OUTPUT SIGNAL FROM ECM. 
  1. Turn the ignition switch to OFF.
  2. Connect the test mode connector at the lower portion of instrument panel (on the driver's side).
  3. Turn the ignition switch to ON.
  4. 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. 
  1. Turn the ignition switch to ON.
  2. 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. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from purge control solenoid valve.
  3. Turn the ignition switch to ON.
  4. 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. 
  1. Turn the ignition switch to OFF.
  2. 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) . >
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.