DTC P1400 - Fuel Tank Pressure Control Solenoid Valve Circuit Low -

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

DTC DETECTING CONDITION:
- Two consecutive driving cycles with malfunction
NOTE: 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: Fuel Tank Pressure Control Solenoid Valve Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK OUTPUT SIGNAL FROM ECM. Turn ignition switch to ON. Measure voltage between ECM and chassis ground. Connector & terminal (B134) No. 4 (+) - Chassis ground (-):	Is the measured value more than 10 V?	Go to step 2.	Go to step 3.
2 CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	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.
3 CHECK HARNESS BETWEEN PRESSURE CONTROL SOLENOID VALVE AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect connectors from pressure control solenoid valve and ECM. Measure resistance of harness between pressure control solenoid valve connector and chassis ground. Connector & terminal (R68) No. 2 - Chassis ground:	Is the measured value more than 1 MΩ?	Go to step 4.	Repair ground short circuit in harness between ECM and pressure control solenoid valve connector.
4 CHECK HARNESS BETWEEN PRESSURE CONTROL SOLENOID VALVE AND ECM CONNECTOR. Measure resistance of harness between ECM and pressure control solenoid valve connector. Connector & terminal (B134) No. 4 - (R68) No. 2:	Is the measured value less than 1 Ω?	Go to step 5.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between ECM and pressure control solenoid valve connector Poor contact in coupling connectors
5 CHECK PRESSURE CONTROL SOLENOID VALVE. Measure resistance between pressure control solenoid valve terminals. Terminals No. 1 - No. 2:	Is the measured value within 10 to 100 Ω?	Go to step 6.	Replace pressure control solenoid valve. < Ref. to PRESSURE CONTROL SOLENOID VALVE . >
6 CHECK POWER SUPPLY TO PRESSURE CONTROL SOLENOID VALVE. Turn ignition switch to ON. Measure voltage between pressure control solenoid valve and chassis ground. Connector & terminal (R68) No. 1 (+) - Chassis ground (-):	Is the measured value more than 10 V?	Go to step 7.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between main relay and pressure control solenoid valve connector Poor contact in coupling connectors Poor contact in main relay connector
7 CHECK POOR CONTACT. Check poor contact in pressure control solenoid valve connector.	Is there poor contact in pressure control solenoid valve connector?	Repair poor contact in pressure control solenoid valve connector.	Contact with SOA service center. NOTE: Inspection by DTM is required, because probable cause is deterioration of multiple parts.