Subaru Legacy 2003 Service Manual page 574

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS BETWEEN KNOCK SEN-
SOR AND ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance between ECM harness
connector and chassis ground.
Connector & terminal
(B135) No. 16 — Chassis ground:
Does the measured value exceed the spec-
ified value?
2 CHECK KNOCK SENSOR.
1) Disconnect connector from knock sensor.
2) Measure resistance between knock sensor
connector terminal and engine ground.
Terminal
No. 2 — Engine ground:
Does the measured value exceed the spec-
ified value?
3 CHECK CONDITION OF KNOCK SENSOR
INSTALLATION.
Is the knock sensor installation bolt tightened
securely?
Value
700 kΩ
700 kΩ
Tightened securely.
EN(H4SO)-177
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair harness
and connector.
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 3. Repair harness
and connector.
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
Replace knock Tighten knock
sensor. <Ref. to sensor installation
FU(H4SO)-29, bolt securely.
Knock Sensor.>
No