DTC P1446 Fuel Tank Sensor Control Valve Circuit Low

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P1446 FUEL TANK SENSOR CONTROL VALVE CIRCUIT LOW , Diagnostic Trouble Code (DTC) Detecting Criteria. >

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

WIRING DIAGRAM:

Fig 1: DTC P1446 Fuel Tank Sensor Control Valve Circuit Low

Courtesy of SUBARU OF AMERICA, INC.

DTC P1446 FUEL TANK SENSOR CONTROL VALVE CIRCUIT LOW DIAGNOSIS

Step	Check	Yes	No
1. CHECK OUTPUT SIGNAL FROM ECM. Turn ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 24 (+) - Chassis ground (-):	Is the voltage 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.	The malfunction indicator light may light up, however, the circuit is returned to the normal status at the moment. (However, the possibility of poor contact still remains.) NOTE: In this case, repair the following: Poor contact in fuel tank sensor control valve connector Poor contact in ECM connector Poor contact in coupling connector
3. CHECK HARNESS BETWEEN FUEL TANK SENSOR CONTROL VALVE AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect the connectors from fuel tank sensor control valve and ECM. Measure the resistance of harness between fuel tank sensor control valve connector and chassis ground. Connector & terminal (R144) No. 1 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 4.	Repair short circuit to ground in harness between ECM and fuel tank sensor control valve connector.
4. CHECK HARNESS BETWEEN FUEL TANK SENSOR CONTROL VALVE AND ECM CONNECTOR. Measure the resistance of harness between ECM and fuel tank sensor control valve connector. Connector & terminal (B134) No. 24 - (R144) No. 1:	Is the resistance 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 fuel tank sensor control valve connector Poor contact in coupling connector
5. CHECK FUEL TANK SENSOR CONTROL VALVE. Measure the resistance between fuel tank sensor control valve terminals. Terminals No. 1 - No. 2:	Is the resistance 10 - 100 Ω?	Go to step 6.	Replace the fuel tank sensor control valve. < Ref. to DRAIN VALVE . >
6. CHECK POWER SUPPLY TO FUEL TANK SENSOR CONTROL VALVE. Turn ignition switch to ON. Measure the voltage between fuel tank sensor control valve and chassis ground. Connector & terminal (R144) No. 2 (+) - Chassis ground (-):	Is the voltage 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 fuel tank sensor control valve Poor contact in coupling connector Poor contact in main relay connector
7. CHECK POOR CONTACT. Check poor contact in fuel tank sensor control valve connector.	Is there poor contact in fuel tank sensor control valve connector?	Repair poor contact in fuel tank sensor control valve connector.	Contact SOA Service Center.