Subaru IMPREZA 2004 Service Manual page 94

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 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 ( − − − − ):
2 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connectors from purge con-
trol solenoid valve and ECM.
3)Measure the resistance of harness between
purge control solenoid valve connector and
engine ground.
Connector & terminal
(E4) No. 2 — Engine ground:
3 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
Measure the resistance of harness between
ECM and purge control solenoid valve of har-
ness connector.
Connector & terminal
(B134) No. 29 — (E4) No. 2:
4 CHECK PURGE CONTROL SOLENOID
VALVE.
1)Remove the purge control solenoid valve.
2)Measure the resistance between purge con-
trol solenoid valve terminals.
Terminals
No. 1 — No. 2:
5 CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1)Turn the ignition switch to ON.
2)Measure the voltage between purge control
solenoid valve and engine ground.
Connector & terminal
(E4) No. 1 (+) — Engine ground ( − − − − ):
Check
Is the voltage more than 10 V? Even if malfunction
Is the resistance more than 1
MΩ?
Is the resistance less than 1
Ω?
Is the resistance 10 — 100 Ω? Go to step 5.
Is the voltage more than 10 V? Go to step 6.
EN(H4SO)(diag)-171
ENGINE (DIAGNOSTICS)
Yes
Go to step 2.
indicator light
lights up, the cir-
cuit has returned
to a normal condi-
tion at this time.
Contact with SUB-
ARU distributor
service.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
Go to step 3. Repair ground
short circuit in har-
ness between
ECM and purge
control solenoid
valve connector.
Go to step 4. Repair open circuit
in harness
between ECM and
purge control sole-
noid valve connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and purge
control solenoid
valve connector
• Poor contact in
coupling connector
Replace the purge
control solenoid
valve. <Ref. to
EC(H4SO)-7,
Purge Control
Solenoid Valve.>
Repair open circuit
in harness
between main
relay and purge
control solenoid
valve connector.
No