Subaru Impreza 2003 Service Manual page 1364

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 the voltage between ECM and
chassis ground.
NOTE:
Purge control solenoid valve operation can be
executed using the Subaru Select Monitor. For
procedure, refer to "Compulsory Valve Opera-
tion Check Mode". <Ref. to EN(H4DOTC)-49,
Compulsory Valve Operation Check Mode.>
Connector & terminal
(B84) No. 16 (+) — 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
(B84) No. 16 (+) — Chassis ground ( − − − − ):
3 CHECK POOR CONTACT.
Check the 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
(B84) No. 16 (+) — 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 — 13 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 the battery
Is the resistance less than 1
Ω?
Is there poor contact in ECM
connector?
EN(H4DOTC)-188
Yes
Go to step 2. Even if malfunc-
tion indicator light
lights up, the cir-
cuit has returned
to a normal condi-
tion at this time. In
this case, repair
the poor contact in
ECM connector.
Go to step 3.
Repair the poor Replace the ECM.
contact in ECM <Ref. to
connector. FU(H4DOTC)-49,
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(H4DOTC)-49,
Engine Control
Module (ECM).>
Replace the purge Go to step 6.
control solenoid
valve <Ref. to
EC(H4DOTC)-7,
Purge Control
Solenoid Valve.>
and ECM <Ref. to
FU(H4DOTC)-49,
Engine Control
Module (ECM).>
Repair the poor Replace the ECM.
contact in ECM <Ref. to
connector. FU(H4DOTC)-49,
Engine Control
Module (ECM).>
No