Subaru Legacy 2004 Service Manual page 911

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OPTION CODE.
2 CHECK HARNESS BETWEEN KNOCK SEN-
SOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM har-
ness connector and chassis ground.
Connector & terminal
(B136) No. 25 — Chassis ground:
3 CHECK KNOCK SENSOR.
1) Disconnect the connector from knock sen-
sor.
2) Measure the resistance between knock
sensor connector terminal and engine ground.
Terminals
No. 2 — Engine ground:
4 CHECK CONDITION OF KNOCK SENSOR
INSTALLATION.
Check
Is the option code EC, EK or
K4?
Is the resistance more than
700 k!?
Is the resistance more than
700 k!?
Is the knock sensor installation
bolt tightened securely?
EN(H4SO 2.5)(diag)-152
Yes
Go to step 2. Refer to EN(H4SO
2.0) section. <Ref.
to EN(H4SO
2.0)(diag)-66, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.
Go to step 3. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
knock sensor and
ECM connector
• Poor contact in
knock sensor con-
nector
• Poor contact in
coupling connector
Go to step 4. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Poor contact in
knock sensor con-
nector
Replace the knock Tighten knock sen-
sensor. <Ref. to sor installation bolt
FU(H4SO 2.5)-23, securely.
Knock Sensor.>
No