Subaru Impreza 2003 Service Manual page 586

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OUTPUT SIGNAL FROM ECM.
1)Turn the ignition switch to OFF.
2)Connect the test mode connector at the
lower portion of instrument panel (on the
driver's side).
3)Turn the ignition switch to ON.
4)While operating the 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)-47, Compul-
sory Valve Operation Check Mode.>
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
2 CHECK OUTPUT SIGNAL FROM ECM.
1)Turn the ignition switch to ON.
2)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.
4 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from purge control
solenoid valve.
3)Turn the ignition switch to ON.
4)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 29 (+) — Chassis ground ( − − − − ):
5 CHECK PURGE CONTROL SOLENOID
VALVE.
1)Turn the ignition switch to OFF.
2)Measure the resistance between purge con-
trol solenoid valve terminals.
Terminals
No. 1 — No. 2:
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Check
Is the voltage 0 — 10 V?
Is the voltage more than 10 V? Go to step 4.
Is there poor contact in ECM
connector?
Is the voltage more than 10 V? Repair battery
Is the resistance less than 1
Ω?
Is there poor contact in ECM
connector?
EN(H4SO)-174
Yes
Go to step 2. Even if malfunc-
tion indicator light
light up, the circuit
has returned to a
normal condition
at this time. In this
case, repair poor
contact in ECM
connector.
Go to step 3.
Repair poor con- Replace the ECM.
tact in ECM con- <Ref. to
nector. FU(H4SO)-48,
Engine Control
Module (ECM).>
Go to step 5.
short circuit in har-
ness between
ECM and purge
control solenoid
valve connector.
After repair,
replace the ECM.
<Ref. to
FU(H4SO)-48,
Engine Control
Module (ECM).>
Replace the purge Go to step 6.
control solenoid
valve <Ref. to
EC(H4SO)-7,
Purge Control
Solenoid Valve.>
and ECM <Ref. to
FU(H4SO)-48,
Engine Control
Module (ECM).>
Repair poor con- Replace the ECM.
tact in ECM con- <Ref. to
nector. FU(H4SO)-48,
Engine Control
Module (ECM).>
No