Subaru Legacy 2002 Service Manual page 1359

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Engine (DIAGNOSTICS)
No.
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 connec-
tor.
Connector & terminal
(B137) No. 19 — (E47) No. 4:
2 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
Measure resistance of harness between ECM
and front oxygen (A/F) sensor connector.
Connector & terminal
(B137) No. 29 — (E47) No. 3:
3 CHECK POOR CONTACT.
Check poor contact in front oxygen (A/F) sen-
sor connector.
Step
Is the resistance less than
1 Ω?
Is the resistance less than
1 Ω?
Is there poor contact in
front oxygen (A/F) sensor
connector?
EN(H6)-152
Check Yes
Go to step 2.
Go to step 3.
Repair poor con-
tact in front oxy-
gen (A/F) sensor
connector.
No
Repair harness
and connector.
NOTE:
In this case,
repair the follow-
ing:
¼ Open circuit in
harness between
ECM and front
oxygen (A/F) sen-
sor connector
¼ Poor contact in
front oxygen (A/F)
sensor connector
¼ Poor contact in
ECM connector
Repair harness
and connector.
NOTE:
In this case,
repair the follow-
ing:
¼ Open circuit in
harness between
ECM and front
oxygen (A/F) sen-
sor connector
¼ Poor contact in
front oxygen (A/F)
sensor connector
¼ Poor contact in
ECM connector
Replace front oxy-
gen (A/F) sensor.
<Ref. to FU(H6)-
43, Front Oxygen
(A/F) Sensor.>