Subaru 2009 IMPREZA Service Manual page 1459

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 29 (+) — Chassis ground (–):
2 CHECK HARNESS BETWEEN ECM AND
PURGE CONTROL SOLENOID VALVE CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
purge control solenoid valve.
3) Measure the resistance between the purge
control solenoid valve connector and engine
ground.
Connector & terminal
(E4) No. 2 — Engine ground:
3 CHECK HARNESS BETWEEN ECM AND
PURGE CONTROL SOLENOID VALVE CON-
NECTOR.
Measure the resistance of harness between
ECM and purge control solenoid valve.
Connector & terminal
(B137) No. 29 — (E4) No. 2:
4 CHECK PURGE CONTROL SOLENOID
VALVE.
1) Remove the purge control solenoid valve.
2) Measure the resistance between purge con-
trol solenoid valve terminals.
Terminals
No. 1 — No. 2:
5 CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between purge control
solenoid valve and engine ground.
Connector & terminal
(E4) No. 1 (+) — Engine ground (–):
Check
Is the voltage 10 V or more?
Is the resistance 1 M or
more?
Is the resistance less than 1 ? Go to step 4.
Is the resistance 10 — 100 ? Go to step 5.
Is the voltage 10 V or more?
EN(H4DOTC)(diag)-238
Yes No
Repair the poor Go to step 2.
contact of ECM
connector.
Go to step 3. Repair the ground
short circuit of har-
ness between
ECM and purge
control solenoid
valve connector.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and purge
control
valve connector
• Poor contact of
coupling connector
Replace the purge
control solenoid
valve. <Ref. to
EC(H4DOTC)-11,
Purge Control
Solenoid Valve.>
Repair the poor Repair the harness
contact of purge and connector.
control solenoid
NOTE:
valve connector.
In this case, repair
the following item:
• Open circuit in
harness between
main relay connec-
tor and purge con-
trol solenoid valve
connector
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor
solenoid