Subaru 2009 IMPREZA Service Manual page 1424

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
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 voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 15 (+) — Chassis ground (–):
Check
Is the voltage 10 V or more?
EN(H4DOTC)(diag)-203
ENGINE (DIAGNOSTICS)
Yes No
Repair the short Repair the poor
circuit to power in contact of ECM
harness between connector.
ECM and second-
ary air combination
valve relay 1 con-
nector.