Subaru Forester 2004 Service Manual page 109

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTIC)
Step
1 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to ON.
2) Disconnect the connector from front oxygen
(A/F) sensor.
3) Measure the voltage of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 26 (+) — Chassis ground (
(B134) No. 33 (+) — Chassis ground (
Check
Is the voltage more than 8 V?
−
):
−
):
EN(H4DOTC 2.5)-108
Yes
Replace the front Repair battery
oxygen (A/F) sen- short circuit in har-
sor. <Ref. to ness between
FU(H4DOTC 2.5)- ECM and front
36, Front Oxygen oxygen (A/F) sen-
(A/F) Sensor.> sor connector.
No