Subaru IMPREZA 2002 Service Manual page 497

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENG I NE ( D I AG NOSTl CS)
Yes
Go to step 2.
Step
CHECK HARNESS BETWEEN KNOCK SEN-
SOR AND ECM CONNECTOR.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
CHECK KNOCK SENSOR.
1)Disconnect the connector from knock sensor.
2)Measure the resistance between knock sen-
sor connector terminal and engine ground.
(8136) No. 4
-
Chassis ground:
Terminal
No. 2
-
Engine ground:
No
Go to step 3.
i
CHECK INPUT SIGNAL FOR ECM.
j)Connect the connectors to ECM and knock
sensor.
2)Turn the ignition switch to ON.
3)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(8136) No. 4 (+)
-
Chassis ground (-):
Replace the knock
sensor. <Ref. to
FU(S0HC)-30,
Knock Sensor.>
Even if MIL lights
up, the circuit has
returned to a nor-
Check
s the resistance less than
400
A2?
Repair ground
short circuit in har-
ness between
knock sensor con-
nector and ECM
connector.
NOTE:
The harness be-
tween both con-
nectors is
shielded. Repaii
short circuit of har-
ness together with
shield.
Repair poor con-
tact in ECM con-
nector.
s the resistance less than 400
:a?
s the voltage more than 2 V?
EN(S0HC)-173
I