Subaru IMPREZA 2002 Service Manual page 410

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
I
CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(8134) No. 23 (+)
-
Chassis ground (-):
I
CHECK FRONT OXYGEN (NF) SENSOR.
1)Turn the ignition switch to OFF.
Check
Does the voltage change less
than 1 .O V by shaking harness
and connector of ECM while
monitoring the value with volt-
age meter?
Is the resistance less than 10
n?
Yes
Repair poor con-
tact in ECM con-
nector.
Repair harness
and connector.
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
No
Go to step
9.
Replace the front
oxygen (NF) sen-
sor. <Ref. to
Fuel.>
FU(S0HC)-50,
I
EN(S0HC)-86