DTC P0447 - Evaporative Emission Control System Vent Control Circuit Open -

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 Vent Control 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. 3 (+) - 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.	Even if MIL lights up, the circuit has returned to a normal condition at this time. (However, the possibility of poor contact still remains.) NOTE: In this case, repair the following: Poor contact in drain valve connector Poor contact in ECM connector Poor contact in coupling connectors
3 CHECK HARNESS BETWEEN DRAIN VALVE AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect connectors from drain valve and ECM. Measure resistance of harness between drain valve connector and chassis ground. Connector & terminal (R143) 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 drain valve connector.
4 CHECK HARNESS BETWEEN DRAIN VALVE AND ECM CONNECTOR. Measure resistance of harness between ECM and drain valve connector. Connector & terminal (B134) No. 3 - (R143) 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 drain valve connector Poor contact in coupling connectors
5 CHECK DRAIN VALVE. Measure resistance between drain valve terminals. Terminals No. 1 - No. 2:	Is the measured value within 10 to 100 Ω?	Go to step 6.	Replace drain valve. < Ref. to DRAIN VALVE . >
6 CHECK POWER SUPPLY TO DRAIN VALVE. Turn ignition switch to ON. Measure voltage between drain valve and chassis ground. Connector & terminal (R143) 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 drain valve Poor contact in coupling connectors Poor contact in main relay connector
7 CHECK POOR CONTACT. Check poor contact in drain valve connector.	Is there poor contact in drain valve connector?	Repair poor contact in drain valve connector.	Contact with SOA service center. NOTE: Inspection by DTM is required, because probable cause is deterioration of multiple parts.