DTC P0452 Evaporative Emission Control System Pressure Sensor Low Input: Wiring Diagram

Fig 1: Evaporative Emission Control System Pressure Sensor Wiring Diagram (Low Input)

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK CURRENT DATA. Turn the ignition switch to ON. Read the data of fuel tank pressure sensor signal using the Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Refer to , SUBARU SELECT MONITOR . General scan tool For detailed operation procedures, refer to the general scan tool operation manual.	Is the measured value less than -7.41 kPa (-55.6 mmHg, -2.19 inHg)?	Go to step 2.	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 FUEL TANK PRESSURE SENSOR POWER SUPPLY. Turn the ignition switch to OFF. Disconnect the connector from the fuel tank pressure sensor. Turn the ignition switch to ON. Measure the voltage between the fuel tank pressure sensor connector and chassis ground. Connector & terminal (R47) No. 3 (+) - Chassis ground (-):	Is the voltage 4.5 V or more?	Go to step 3.	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit of harness between ECM and fuel tank pressure sensor connector Poor contact of ECM connector Poor contact of coupling connector
3 CHECK HARNESS BETWEEN ECM AND FUEL TANK PRESSURE SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from ECM. Measure the resistance of harness between the ECM and fuel tank pressure sensor connector. Connector & terminal (B136) No. 21 - (R47) No. 2:	Is the resistance less than 1 Ω?	Go to step 4.	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit of harness between ECM and fuel tank pressure sensor connector Poor contact of coupling connector
4 CHECK HARNESS BETWEEN ECM AND FUEL TANK PRESSURE SENSOR CONNECTOR. Measure the resistance between ECM and chassis ground. Connector & terminal (B136) No. 21 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 5.	Repair the ground short circuit of harness between ECM and fuel tank pressure sensor connector.
5 CHECK FOR POOR CONTACT. Check for poor contact between the ECM and fuel tank pressure sensor connector.	Is there poor contact of the ECM or fuel tank pressure sensor connector?	Repair the poor contact of the ECM or fuel tank pressure sensor connector.	Replace the fuel tank pressure sensor. Refer to FUEL TANK PRESSURE SENSOR , Fuel Tank Pressure Sensor.