DTC P2421: EVAP System Vent Valve Stuck Open: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition.

Trouble symptom: 

• Gasoline odor.
• The fuel lid does not open even if the fuel door release switch is pressed.

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DATA MONITOR  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, read the values of [Electric Vent Solenoid Value Output] and [Electric Vent Solenoid Value Terminal] of the data monitor.
      NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .

   Is the value of [Electric Vent Solenoid Value Terminal] "[Close]" when the value of [Electric Vent Solenoid Value Output] is "[Close]"?

   Yes  : Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

   No  : Go to  2.

2. CHECK OUTPUT SIGNAL OF ECM (SHORT TO POWER SUPPLY)  .
   1. Turn the ignition switch to ON.
   2. Measure the voltage between ECM connector and engine ground.

      Connector & terminal 

      (B134) No. 23 (+) - Engine ground (-):

   Is the voltage 10 V or more?

   Yes  : Go to  3.

   No  : Go to  4.

3. CHECK FOR POOR CONTACT  .

   Check for poor contact of ECM connector.

   Is there poor contact of ECM connector?

   Yes  : Repair the poor contact of ECM connector.

   No  : Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary open or short circuit of harness or temporary poor contact of connector may be the cause.
4. CHECK POWER SUPPLY TO Electric Vent Solenoid Valve ASSEMBLY (OPEN)  .

   Measure the voltage between Electric Vent Solenoid Valve ASSEMBLY connector and chassis ground.

   Connector & terminal 

   (AD94) No. 2 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes  : Go to  5.

   No  : Repair the power supply circuit.

5. CHECK HARNESS BETWEEN ECM AND Electric Vent Solenoid Valve ASSEMBLY (SHORT TO GROUND)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Disconnect the connector from Electric Vent Solenoid Valve ASSEMBLY.
   4. Measure the resistance between Electric Vent Solenoid Valve ASSEMBLY connector and chassis ground.

      Connector & terminal 

      (AD94) No. 1 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  6.

   No  : Repair the short circuit to ground in harness between ECM connector and Electric Vent Solenoid Valve ASSEMBLY connector.

6. CHECK HARNESS BETWEEN ECM AND Electric Vent Solenoid Valve ASSEMBLY (OPEN)  .

   Measure the resistance of harness between ECM connector and Electric Vent Solenoid Valve ASSEMBLY.

   Connector & terminal 

   (B134) No. 23 - (AD94) No. 1:

   Is the resistance less than 1 Ω?

   Yes  : Go to  7.

   No  : Check the harnesses and connectors, and repair or replace them if necessary.

   NOTE: In this case, repair the following item:

   • Open circuit in harness between ECM connector and Electric Vent Solenoid Valve ASSEMBLY
   • Poor contact of coupling connector
7. CHECK Electric Vent Solenoid Valve ASSEMBLY  .
   1. Remove the Electric Vent Solenoid Valve ASSEMBLY.
   2. Check Electric Vent Solenoid Valve ASSEMBLY. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DO (HEV))>ELECTRIC VENT SOLENOID VALVE ASSEMBLY>INSPECTION .

   Is the check result OK?

   Yes  : Repair the poor contact of Electric Vent Solenoid Valve ASSEMBLY connector.

   No  : Replace Electric Vent Solenoid Valve ASSEMBLY. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DO (HEV))>ELECTRIC VENT SOLENOID VALVE ASSEMBLY .