DTC P0452 - Evaporative Emission Control System Pressure Sensor Low Input -

WARNING: This page is about a different variant/trim than selected.

DTC DETECTING CONDITION:
- Two consecutive driving cycles with malfunction

CAUTION: After repair or replacement of malfunctioning parts, conduct Clear Memory Mode < Ref. to OPERATION , CLEAR MEMORY MODE > and INSPECTION MODE < Ref. to OPERATION , INSPECTION MODE. >

WIRING DIAGRAM:

Fig 1: Evaporative Emission Control System Pressure Sensor Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK CURRENT DATA. Turn ignition switch to OFF. Remove fuel filler cap. Install fuel filler cap. Turn ignition switch to ON. Read the data of fuel tank pressure sensor signal using Subaru Select Monitor or the general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR . > General scan tool For detailed operation procedures, refer to the General Scan Tool Instruction Manual.	Is the measured value less than -2.8 kPa (-21.0 mmHg, -0.827 inHg)?	Go to step 2.	Even if MIL lights up, the circuit has returned to a normal condition at this time.
2 CHECK POWER SUPPLY TO FUEL TANK PRESSURE SENSOR. Measure voltage between ECM connector and chassis ground. Connector & terminal (B135) No. 3 (+) - Chassis ground (-):	Is the measured value more than 4.5 V?	Go to step 4.	Go to step 3.
3 CHECK POWER SUPPLY TO FUEL TANK PRESSURE SENSOR. Measure voltage between ECM connector and chassis ground. Connector & terminal (B135) No. 3 (+) - Chassis ground (-):	Is the measured value more than 4.5 V when shaking harness and connector of ECM?	Repair poor contact in ECM connector.	Contact with SOA (distributor) service. NOTE: Inspection by DTM is required, because probable cause is deterioration of multiple parts.
4 CHECK INPUT SIGNAL FOR ECM. Measure voltage between ECM and chassis ground. Connector & terminal (B135) No. 26 (+) - Chassis ground (-):	Is the measured value less than 0.2 V?	Go to step 6.	Go to step 5.
5 CHECK INPUT SIGNAL FOR ECM. (USING SUBARU SELECT MONITOR.) Read data of fuel tank pressure sensor signal using Subaru Select Monitor. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR . >	Does the measured value change when shaking harness and connector of ECM?	Repair poor contact in ECM connector.	Go to step 6.
6 CHECK HARNESS BETWEEN ECM AND COUPLING CONNECTOR IN REAR WIRING HARNESS. Turn ignition switch to OFF. Remove rear seat cushion. Separate rear wiring harness and fuel tank cord. Turn ignition switch to ON. Measure voltage between rear wiring harness connector and chassis ground. Connector & terminal (R134) No. 8 (+) - Chassis ground (-):	Is the measured value more than 4.5 V?	Go to step 7.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between ECM and rear wiring harness connector Poor contact in coupling connector
7 CHECK HARNESS BETWEEN ECM AND COUPLING CONNECTOR IN REAR WIRING HARNESS. Turn ignition switch to OFF. Disconnect connector from ECM. Measure resistance of harness between ECM and rear wiring harness connector. Connector & terminal (B135) No. 19 - (R134) No. 2:	Is the measured value less than 1 Ω?	Go to step 8.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between ECM and rear wiring harness connector Poor contact in coupling connector Poor contact in joint connector
8 CHECK HARNESS BETWEEN ECM AND COUPLING CONNECTOR IN REAR WIRING HARNESS. Measure resistance of harness between rear wiring harness connector and chassis ground. Connector & terminal (R134) No. 2 - Chassis ground:	Is the measured value more than 1 MΩ?	Go to step 9.	Repair ground short circuit in harness between ECM and rear wiring harness connector.
9 CHECK FUEL TANK CORD. Disconnect connector from fuel tank pressure sensor. Measure resistance of fuel tank cord. Connector & terminal (R135) No. 8 - (R47) No. 3:	Is the measured value less than 1 Ω?	Go to step 10 .	Repair open circuit in fuel tank cord.
10 CHECK FUEL TANK CORD. Measure resistance of fuel tank cord. Connector & terminal (R135) No. 2 - (R47) No. 1:	Is the measured value less than 1 Ω?	Go to step 11 .	Repair open circuit in fuel tank cord.
11 CHECK FUEL TANK CORD. Measure resistance of harness between fuel tank pressure sensor connector and chassis ground. Connector & terminal (R47) No. 2 - Chassis ground:	Is the measured value more than 1 MΩ?	Go to step 12 .	Repair ground short circuit in fuel tank cord.
12 CHECK POOR CONTACT. Check poor contact in fuel tank pressure sensor connector.	Is there poor contact in fuel tank pressure sensor connector?	Repair poor contact in fuel tank pressure sensor connector.	Replace fuel tank pressure sensor. < Ref. to FUEL TANK PRESSURE SENSOR . >