DTC P04F0: EVAP System High Pressure Purge Line (CPC2) Performance: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

Improper idling

1. CHECK DTC. 

   Read the engine DTC using the Subaru Select Monitor or general scan tool. Refer to ENGINE (DIAGNOSTICS) (W/O STI)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC other than P04F0 displayed? (Current malfunction)

   Yes:  Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Refer to ENGINE (DIAGNOSTICS) (W/O STI)>LIST OF DIAGNOSTIC TROUBLE CODE (DTC)

   No:  Go to  2.

2. CHECK PIPING BETWEEN PURGE CONTROL VALVE 2 AND TURBOCHARGER. 

   Check the piping between the purge control valve 2 and the turbocharger.

   Is there dislocation of the piping between the purge control valve 2 and the turbocharger?

   Yes:  Repair or replace the piping between the purge control valve 2 and the turbocharger. Refer to INTAKE (INDUCTION) (W/O STI)>TURBOCHARGER .

   No:  Go to  3.

3. CHECK PIPING BETWEEN PURGE CONTROL VALVE 2 AND TURBOCHARGER. 

   Check the piping between the purge control valve 2 and the turbocharger.

   Is there clogging in the piping between the purge control valve 2 and the turbocharger?

   Yes:  Repair or replace the piping between the purge control valve and the turbocharger. Refer to INTAKE (INDUCTION) (W/O STI)>TURBOCHARGER .

   No:  Go to  4.

4. CHECK PURGE CONTROL VALVE 2. 

   Check the purge control valve 2.

   Is there closed or open stuck state in the purge control valve 2?

   Yes:  Repair or replace the purge control valve 2 or leak check valve. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>PCV VALVE . Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>LEAK CHECK VALVE ASSEMBLY .

   No:  Go to  5.

5. CHECK PURGE CONTROL VALVE 1. 

   Check the main body of the purge control valve 1.

   Is there any leakage in the main body of the purge control valve 1?

   Yes:  Repair or replace the purge control valve 1. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>PURGE CONTROL SOLENOID VALVE .

   No:  Go to  6.

6. CHECK EVAPORATIVE EMISSION CONTROL SYSTEM LINE. 
   1. Turn the ignition switch to OFF.
   2. Make sure that the delivery mode fuse is removed.

   Are there holes, cracks, clogging, or disconnection, misconnection of hoses or pipes in evaporative emission control system?

   Yes:  Repair or replace the hoses or pipes.

   No:  Go to  7.

7. CHECK VACUUM PUMP OPERATION OF LEAK CHECK VALVE ASSEMBLY. 

   Check the vacuum pump operation of the leak check valve assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>LEAK CHECK VALVE ASSEMBLY>INSPECTION .

   Does the vacuum pump operate?

   Yes:  Go to  8.

   No:  Replace the leak check valve assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>LEAK CHECK VALVE ASSEMBLY .

8. CHECK SWITCHING VALVE OPERATION OF LEAK CHECK VALVE ASSEMBLY. 

   Check the switching valve operation of the leak check valve assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>LEAK CHECK VALVE ASSEMBLY>INSPECTION .

   Does the switching valve operate?

   Yes:  End.

   No:  Replace the leak check valve assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (W/O STI)>LEAK CHECK VALVE ASSEMBLY .