Subaru Legacy 2003 Service Manual page 1968

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INPUT SIGNAL TO ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 11 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
2 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?
3 CHECK HARNESS BETWEEN EXHAUST
VALVE CONTROL DUTY SOLENOID VALVE
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust
valve control duty solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 11 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
4 CHECK EXHAUST VALVE CONTROL DUTY
SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between exhaust
valve control duty solenoid valve terminals.
Terminals
No. 11 — No. 12:
Is the measured value less than the speci-
fied value?
5 CHECK POOR CONTACT.
Check poor contact in ECM and exhaust valve
control duty solenoid valve connectors.
Is there poor contact in ECM exhaust valve
control duty solenoid valve connectors?
Value
10 V
There is poor contact.
10 V
1 Ω
There is poor contact.
EN(H4DOSTC)-129
ENGINE (DIAGNOSTICS)
Yes
Go to step 3. Go to step 2.
Repair the poor Replace the ECM.
contact in ECM <Ref. to
connector. FU(H4DOSTC)-
40, Engine Con-
trol Module.>
Repair the battery Go to step 4.
short circuit in har-
ness between
ECM and exhaust
valve control duty
solenoid valve
connector. After
repair, replace the
ECM. <Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>
Replace the Go to step 5.
exhaust valve con-
trol duty solenoid
valve <Ref. to
IN(H4DOSTC)-19,
Solenoid Box
Assembly.> and
ECM <Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>
Repair the poor Replace the ECM.
contact in ECM <Ref. to
connector. FU(H4DOSTC)-
40, Engine Con-
trol Module.>
No