Subaru 2009 IMPREZA Service Manual page 669

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
(B136) No. 28 (+) — Chassis ground (–):
2 CHECK HARNESS BETWEEN ECM AND
PRESSURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the ECM
and pressure control solenoid valve.
3) Measure the resistance between pressure
control solenoid valve and chassis ground.
Connector & terminal
(R68) No. 2 — Chassis ground:
3 CHECK HARNESS BETWEEN ECM AND
PRESSURE CONTROL SOLENOID VALVE.
Measure the resistance of harness between
ECM and pressure control solenoid valve con-
nector.
Connector & terminal
(B136) No. 28 — (R68) No. 2:
4 CHECK PRESSURE CONTROL SOLENOID
VALVE.
Measure the resistance between pressure con-
trol solenoid valve terminals.
Terminals
No. 1 — No. 2:
5 CHECK POWER SUPPLY TO THE PRES-
SURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between pressure con-
trol solenoid valve and chassis ground.
Connector & terminal
(R68) No. 1 (+) — Chassis 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(H4SO)(diag)-252
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 pressure
control solenoid
valve connector.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and pressure
control
valve connector
• Poor contact of
coupling connector
Replace the pres-
sure control sole-
noid valve. <Ref. to
EC(H4SO)-16,
Pressure Control
Solenoid Valve.>
Repair the poor Repair the harness
contact of pressure and connector.
control solenoid
NOTE:
valve connector.
In this case, repair
the following item:
• Open circuit in
harness between
main relay
pressure
solenoid
connector
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor
solenoid
and
control
valve