DTC P0451: EVAP System Pressure Sensor/Switch Circuit Range/Performance: Notes

1. - 

DTC detecting condition:  Detected when refueling is performed twice under the faulty condition.

Trouble symptom:  The fuel lid does not open even if the fuel door release switch is pressed.

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .

   Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC other than P0451 displayed? (Current malfunction)

   Yes:  Check the appropriate DTC using the "Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DO (HEV))>DIAGNOSTIC TROUBLE CODE (DTC) .

   No:  Go to  2.

2. CHECK TANK PRESSURE SENSOR  .
   1. Turn the ignition switch to OFF.
   2. Press the fuel door release switch to open the fuel lid.
   3. Wait for one minute or more.
   4. Open the fuel cap.
   5. Turn the ignition switch to ON.
   6. Using the Subaru Select Monitor, read the value of [Fuel Tank Pressure Sensor] of the data monitor.
      NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .

      Is the value of [Fuel Tank Pressure Sensor] -2.65 - 3.52 [kPa] (-19.88 - 26.41 mmHg, -0.78 - 1.04 inHg, -0.38 - 0.51 psi)?

      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:  Replace the circulate tube assembly. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (HEV))>CIRCULATE TUBE ASSY .

      NOTE: Tank pressure sensor cannot be disassembled.