DTC P1400 Fuel Tank Pressure Control Solenoid Valve Circuit Low

WARNING: This page is about a different car, the 2006 Subaru Outback. However, it is still accessible from the selected car via links, so may be relevant.

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P1400 FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT LOW , Diagnostic Trouble Code (DTC) Detecting Criteria. >

CAUTION: After repair or replacement of faulty parts, perform Clear Memory Mode < Ref. to OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM:

Fig 1: Fuel Tank Pressure Control Solenoid Valve - Wiring Diagram

DTC P1400 FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT LOW - DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK OUTPUT SIGNAL OF ECM. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B136) No. 28 (+) - Chassis ground (-):	Is the voltage more than 10 V?	Go to step 2.	Go to step 3 .
2 CHECK POOR CONTACT. Check the poor contact of ECM connector.	Is there poor contact in ECM connector?	Repair the poor contact of ECM connector.	Contact with SOA Service Center.
3 CHECK HARNESS BETWEEN PRESSURE CONTROL SOLENOID VALVE AND ECM CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from the pressure control solenoid valve and ECM. Measure the resistance of harness between pressure control solenoid valve connector and chassis ground. Connector & terminal (R68) No. 2 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 4.	Repair the ground short circuit of harness between ECM and pressure control solenoid valve connector.
4 CHECK HARNESS BETWEEN PRESSURE CONTROL SOLENOID VALVE AND ECM CONNECTOR. Measure the resistance of harness between ECM and pressure control solenoid valve connector. Connector & terminal (B136) No. 28 - (R68) No. 2:	Is the resistance less than 1 D?	Go to step 5.	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between ECM and pressure control solenoid valve connector Poor contact in coupling connector
5 CHECK PRESSURE CONTROL SOLENOID VALVE. Measure the resistance between pressure control solenoid valve terminals. Terminals No. 1 - No. 2:	Is the resistance between 10 and 100Ω?	Go to step 6.	Replace the pressure control solenoid valve. < Ref. to PRESSURE CONTROL SOLENOID VALVE . >
6 CHECK POWER SUPPLY TO THE PRESSURE CONTROL SOLENOID VALVE. Turn the ignition switch to ON. Measure the voltage between pressure control solenoid valve and chassis ground. Connector & terminal (R68) No. 1 (+) - Chassis ground (-):	Is the voltage more than 10 V?	Go to step 7.	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between main relay and pressure control solenoid valve connector Poor contact in coupling connector Poor contact in main relay connector
7 CHECK POOR CONTACT. Check poor contact of pressure control solenoid valve connector.	Is there poor contact of the pressure control solenoid valve connector?	Repair the poor contact of pressure control solenoid valve connector.	Contact with SOA Service Center.