Subaru Legacy 2003 Service Manual page 598

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to OFF.
2) Connect test mode connector at the lower
portion of instrument panel (on the driver's
side), to the side of the center console box.
3) Turn ignition switch to ON.
4) While operating purge control solenoid
valve, measure voltage between ECM and
chassis ground.
NOTE:
Purge control solenoid valve operation can be
executed using Subaru Select Monitor. For pro-
cedure, refer to "Compulsory Valve Operation
Check Mode". <Ref. to EN(H4SO)-48, Compul-
sory Valve Operation Check Mode.>
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
2 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?
4 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from purge control
solenoid valve.
3) Turn ignition switch to ON.
4) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
5 CHECK PURGE CONTROL SOLENOID
VALVE.
1) Turn ignition switch to OFF.
2) Measure resistance between purge control
solenoid valve terminals.
Terminals
No. 1 — No. 2:
Is the measured value less than the speci-
fied value?
Value
10 V
10 V
There is poor contact.
10 V
1 Ω
EN(H4SO)-201
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Even if MI light up,
the circuit has
returned to a nor-
mal condition at
this time. In this
case, repair poor
contact in ECM
connector.
Go to step 4. Go to step 3.
Repair poor con- Replace ECM.
tact in ECM con- <Ref. to
nector. FU(H4SO)-45,
Engine Control
Module.>
Repair battery Go to step 5.
short circuit in har-
ness between
ECM and purge
control solenoid
valve connector.
After repair,
replace ECM.
<Ref. to
FU(H4SO)-45,
Engine Control
Module.>
Replace purge Go to step 6.
control solenoid
valve <Ref. to
EC(H4SO)-7,
Purge Control
Solenoid Valve.>
and ECM <Ref. to
FU(H4SO)-45,
Engine Control
Module.>
No