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DTC P2420: EVAP System Switching Valve Control Circuit High: Notes

DTC detecting condition:

Immediately at fault recognition

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CLEAR MEMORY MODE>OPERATION , and inspection mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>INSPECTION MODE>PROCEDURE ..
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

G11577180

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the leak check valve assembly.
3. Turn the ignition switch to ON.
4. Measure the voltage between leak check valve assembly and chassis ground.
  Connector & terminal
  
  (R400) No. 1 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes: Repair the short circuit to power in harness between ECM connector and leak check valve assembly connector.

No: Go to 2.
CHECK LEAK CHECK VALVE ASSEMBLY.
1. Turn the ignition switch to OFF.
2. Check the switching valve of the leak check valve assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (EXCEPT FOR STI)>LEAK CHECK VALVE ASSEMBLY>INSPECTION>CHECK SWITCHING VALVE .
Is the check result OK?

Yes: Repair the poor contact in the leak check valve assembly connector.

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