Subaru IMPREZA 2002 Service Manual page 464

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENG IN E (DIAGNOSTICS)
Step
I
CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (NF) SENSOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminals
(8136)
No.
6
-
Chassis ground:
(8136) No. 7
-
Chassis ground:
(8136)
No.
19
-
Chassis ground:
(8136)
No.
20
-
Chassis ground:
i CHECK EXHAUST SYSTEM.
Check exhaust system parts.
NOTE:
Check the following items.
*Loose installation of portions
*Damage (crack, hole etc.) of parts
*Looseness of front oxygen (NF) sensor
*Looseness and ill fitting of parts between front
oxygen (NF) sensor and rear oxygen sensor
Check
Is the resistance more than
1
MR?
Is there a fault in exhaust sys-
tem?
Yes
20 to step 6.
3epair or replace
aulty parts.
No
Repair ground
short circuit
between ECM and
front oxygen (NF)
sensor.
Replace the front
oxygen (NF) sen-
sor.
<Ref. to
Front Oxygen
(A/
F) Sensor.>
FU(S0HC)-43,
EN(S0HC)-140