Subaru Legacy 2003 Service Manual page 548

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from ECM and front
oxygen (A/F) sensor connector.
3) Measure resistance of harness between
ECM and front oxygen (A/F) sensor con-
nector.
Connector & terminal
(B136) No. 13 — (E18) No. 1:
(B136) No. 22 — (B18) No. 2:
Is the measured value less than the speci-
fied value?
2 CHECK POOR CONTACT.
Chack poor contact in front oxygen (A/F) sen-
sor connector.
Is there poor contact in front oxygen (A/F) sen-
sor connector?
Value
1 Ω
There is poor contact.
EN(H4SO)-151
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and fornt
oxygen (A/F) sen-
sor connector
• Poor contact in
front oxygen (A/F)
sensor connector
• Poor contact in
ECM connector
Repair poor con- Replace front oxy-
tact in front oxygen gen (A/F) sensor.
(A/F) sensor con- <Ref. to
nector. FU(H4SO)-41,
Front Oxygen (A/
F) Sensor.>
No