DTC P0448 - Evaporative Emission Control System Vent Control Circuit Shorted -

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 OFF. Connect test mode connector at the lower portion of instrument panel (on the driver's side). Turn ignition switch to ON. While operating drain valve, measure voltage between ECM and chassis ground. NOTE: Drain valve operation can be executed using Subaru Select Monitor. For procedure, < Ref. to COMPULSORY VALVE OPERATION CHECK MODE . > Connector & terminal (B134) No. 3 (+) - Chassis ground (-):	Is the measured value more than 10 V?	Go to step 2.	Even if MIL light up, the circuit has returned to a normal condition at this time. In this case, repair poor contact in ECM connector.
2 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 4.	Go to step 3.
3 CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	Repair poor contact in ECM connector.	Replace ECM. < Ref. to ENGINE CONTROL MODULE . >
4 CHECK HARNESS BETWEEN DRAIN VALVE AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect connector from drain valve. 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?	Repair battery short circuit in harness between ECM and drain valve connector. After repair, replace ECM. < Ref. to ENGINE CONTROL MODULE . >	Go to step 5.
5 CHECK DRAIN VALVE. Turn ignition switch to OFF. Measure resistance between drain valve terminals. Terminals No. 1 - No. 2:	Is the measured value less than 1 Ω?	Replace drain valve < Ref. to DRAIN VALVE > and ECM < Ref. to ENGINE CONTROL MODULE . >	Go to step 6.
6 CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	Repair poor contact in ECM connector.	Replace ECM. < Ref. to ENGINE CONTROL MODULE . >