Subaru Forester 2004 Service Manual page 73

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTIC)
Step
6 CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between front oxy-
gen (A/F) sensor connector terminals.
Terminals
No. 1 — No. 2:
Check
Is the resistance less than 10
Ω?
EN(H4DOTC 2.5)-72
Yes
Repair the harness Replace the front
and connector. oxygen (A/F) sen-
sor. <Ref. to
NOTE:
FU(H4DOTC 2.5)-
In this case repair
36, Front Oxygen
the following:
(A/F) Sensor.>
• Open or ground
short circuit in har-
ness between front
oxygen (A/F) sen-
sor and ECM con-
nector
• Poor contact in
front oxygen (A/F)
sensor connector
• Poor contact in
ECM connector.
No