Subaru 2009 IMPREZA Service Manual page 1421

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 1 CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
secondary air combination valve relay 1.
3) Measure the resistance of harness between
ECM and secondary air combination valve relay
1 connector.
Connector & terminal
(B135) No. 15 — (F9) No. 2:
2 CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 1 CONNECTOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 15 — Chassis ground:
Check
Is the resistance less than 1 ? Go to step 2.
Is the resistance 1 M or
more?
EN(H4DOTC)(diag)-200
Yes No
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and second-
ary air combination
valve relay 1 con-
nector
• Poor contact of
coupling connector
Even if DTC is Repair the short
detected, the cir- circuit to ground in
cuit has returned to harness between
a normal condition ECM and second-
at this time. Repro- ary air combination
duce the failure, valve relay 1 con-
and then perform nector.
the diagnosis
again.
NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.