Subaru Legacy 2003 Service Manual page 2044

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
(B136) No. 1 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
2 CHECK HARNESS BETWEEN EXHAUST
VALVE CONTROL SOLENOID VALVE (POS-
ITIVE PRESSURE) AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from exhaust
valve control solenoid valve (positive pres-
sure) and ECM.
3) Measure the resistance of harness
between exhaust valve control solenoid
valve (positive pressure) connector and
engine ground.
Connector & terminal
(B220) No. 8 — Engine ground:
Does the measured value exceed the spec-
ified value?
3 CHECK HARNESS BETWEEN EXHAUST
VALVE CONTROL SOLENOID VALVE (POS-
ITIVE PRESSURE) AND ECM CONNECTOR.
Measure the resistance of harness between
ECM and exhaust valve control solenoid valve
(positive pressure) of harness connector.
Connector & terminal
(B136) No. 1 — (B220) No. 8:
Does the measured value exceed the specified
value?
4 CHECK EXHAUST VALVE CONTROL SOLE-
NOID VALVE (POSITIVE PRESSURE).
Measure the resistance between exhaust
valve control solenoid valve (positive pressure)
terminals.
Terminals
No. 7 — No. 8:
Is the measured value within the specified
value?
5 CHECK POWER SUPPLY TO EXHAUST
VALVE CONTROL SOLENOID VALVE (POS-
ITIVE PRESSURE).
1) Turn the ignition switch to ON.
2) Measure the voltage between exhaust
valve control solenoid valve (positive pres-
sure) and engine ground.
Connector & terminal
(B220) No. 7 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
Value
10 V
1 MΩ
1 MΩ
37 — 44 Ω
10 V
EN(H4DOSTC)-205
ENGINE (DIAGNOSTICS)
Yes
Even if MI lights Go to step 2.
up, the circuit has
returned to a nor-
mal condition at
this time. Contact
with your Subaru
distributor.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
Repair the ground Go to step 3.
short circuit in har-
ness between
ECM and exhaust
valve control sole-
noid valve (posi-
tive pressure)
connector.
Go to step 4. Repair the open
circuit in harness
between ECM and
exhaust valve con-
trol solenoid valve
(positive pres-
sure) connector.
Go to step 5. Replace the
exhaust valve con-
trol solenoid valve
(positive pres-
sure). <Ref. to
IN(H4DOSTC)-19,
Solenoid Box
Assembly.>
Go to step 6. Repair open circuit
in harness
between main
relay and exhaust
valve control sole-
noid valve (posi-
tive pressure)
connector.
No