Subaru Legacy 2003 Service Manual page 2002

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK THROTTLE CABLE.
Does the throttle cable have play for adjust-
ment?
2 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 10 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from idle air con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 10 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 10 (+) — Chassis ground ( − − − − ):
Does the measured value change by shaking
harness and connector of ECM while monitor-
ing the value with voltage meter?
Value
Cable has play correctly.
10 V
10 V
The value changes.
EN(H4DOSTC)-163
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Adjust the throttle
cable. <Ref. to
SP(H4SO)-10,
Accelerator Con-
trol Cable.>
Go to step 3. Go to step 4.
Repair the battery Replace the idle
short circuit in har- air control solenoid
ness between valve <Ref. to
ECM and idle air FU(H4DOSTC)-
control solenoid 35, Idle Air Con-
valve connector. trol Solenoid
After repair, Valve.> and
replace the ECM. replace ECM
<Ref. to <Ref. to
FU(H4DOSTC)- FU(H4DOSTC)-
40, Engine Con- 40, Engine Con-
trol Module.> trol Module.>.
Repair the battery Contact SUBARU
short circuit in har- distributor service.
ness between
NOTE:
ECM and idle air
Insepction by DTM
control solenoid
is required,
valve connector.
cause
After repair,
cause is deteriora-
replace the ECM.
tion of
<Ref. to
parts.
FU(H4DOSTC)-
40, Engine Con-
trol Module.>
No
be-
probable
multiple