Subaru Legacy 2003 Service Manual page 2038

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INPUT SIGNAL TO ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 22 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
2 CHECK HARNESS BETWEEN INTAKE AIR
VALVE CONTROL SOLENOID VALVE AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from intake air
valve control solenoid valve and ECM.
3) Measure the resistance of harness
between intake air valve control solenoid
valve connector and engine ground.
Connector & terminal
(B220) No. 10 — Engine ground:
Does the measured value exceed the spec-
ified value?
3 CHECK HARNESS BETWEEN INTAKE AIR
VALVE CONTROL SOLENOID VALVE AND
ECM CONNECTOR.
Measure the resistance of harness between
ECM and intake air valve control solenoid
valve of harness connector.
Connector & terminal
(B137) No. 22 — (B220) No. 10:
Is the measured value less than the specified
value?
4 CHECK INTAKE AIR VALVE CONTROL SO-
LENOID VALVE.
Measure the resistance between intake air
valve control solenoid valve terminals.
Terminals
No. 9 — No. 10:
Is the measured value within the specified
value?
5 CHECK POWER SUPPLY TO INTAKE AIR
VALVE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between intake air
valve control solenoid valve and engine
ground.
Connector & terminal
(B220) No. 9 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
Value
10 V
1 MΩ
1 Ω
37 — 44 Ω
10 V
EN(H4DOSTC)-199
ENGINE (DIAGNOSTICS)
Yes
Even if MI lights Go to step 2.
up, the circuit has
returned to a nor-
mal condition at
this time. Contact
SUBARU distribu-
tor service.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
Go to step 3. Repair the ground
short circuit in har-
ness between
ECM and intake
air valve control
solenoid valve
connector.
Go to step 4. Repair the open
circuit in harness
between ECM and
intake air valve
control solenoid
valve connector.
Go to step 5. Replace the intake
air valve control
solenoid valve.
<Ref. to
IN(H4DOSTC)-19,
Solenoid Box
Assembly.>
Go to step 6. Repair the open
circuit in harness
between main
relay and intake air
valve control sole-
noid valve connec-
tor.
No