DTC P0452: EVAP System (CPC) Pressure Sensor/Switch Circuit Low: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DATA MONITOR  .
   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 [kPa] (-19.88 mmHg, -0.78 inHg) or less?

      Yes:  Go to  2.

      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 poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK TANK PRESSURE SENSOR POWER SUPPLY (SHORT TO GROUND)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the tank pressure sensor.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between the tank pressure sensor and chassis ground.

      Connector and terminal 

      (AD93) No. 3 (+) -Chassis ground (-):

      Is the voltage 4.5 V or more?

      Yes:  Go to  3.

      No:  Repair the harness and connector.

      NOTE: In this case, repair the following item:

      • Open circuit in harness between ECM connector and tank pressure sensor connector
      • Poor contact of ECM connector
      • Poor contact of coupling connector
3. CHECK HARNESS BETWEEN ECM AND TANK PRESSURE SENSOR (SHORT TO GROUND)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Measure the resistance between ECM connector and chassis ground.

      Connector and terminal 

      (B134) No. 59 -Chassis ground:

      Is the resistance 1 MΩ or more?

      Yes:  Go to  4.

      No:  Repair the short circuit to ground in harness between ECM connector and tank pressure sensor connector.

4. CHECK FOR POOR CONTACT  .

   Check for poor contact of tank pressure sensor connector.

   Is there poor contact in tank pressure sensor connector?

   Yes:  Repair the poor contact of tank pressure sensor connector.

   No:  Replace the circulate tube assembly. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO(HEV))>CIRCULATE TUBE ASSY .

   NOTE: Tank pressure sensor cannot be disassembled.