Subaru 2002 IMPREZA Service Manual page 314

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
r
CHECK FRONT OXYGEN (NF) SENSOR.
Check Yes
Is the resistance less than 10
Repair harness
2)Measure the resistance between front oxy-
gen (NF) sensor connector terminals.
Terminals
NO. 2 -NO. 1:
1)Turn the ignition switch to OFF.
R?
NOTE:
In this case, repair
the following:
Open or ground
short
circuit in har-
ness between front
oxygen
(NF)
sen-
sor
and ECM con-
nector
Poor contact in
front oxygen (NF)
sensor connector
Poor contact in
ECM connector
and connector.
No
Replace the front
oxygen (NF) sen-
sor. <Ref. to
FU(D0HC
TURBO)-42, Front
Oxygen (NF) Sen-
sor.>
EN(D0HC TURBO)-QO