Subaru 2009 IMPREZA Service Manual page 604

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
KNOCK SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B134) No. 15 — (B134) No. 29:
2 CHECK KNOCK SENSOR.
1) Disconnect the connector from knock sen-
sor.
2) Measure the resistance between knock
sensor terminals.
Terminals
No. 1 — No. 2:
Check
Is the resistance 600 k or
more?
Is the resistance 600 k or
more?
EN(H4SO)(diag)-187
ENGINE (DIAGNOSTICS)
Yes No
Go to step 2. Repair the poor
contact of ECM
connector.
Replace the knock Repair the harness
sensor. <Ref. to and connector.
FU(H4SO)-30,
NOTE:
Knock Sensor.>
In this case, repair
the following item:
• Open circuit in
harness between
ECM and knock
sensor connector
• Poor contact of
knock sensor con-
nector
• Poor contact of
coupling connector