Subaru Legacy 2003 Service Manual page 2018

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 8 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value in neutral position?
2 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis
ground.
Connector & terminal
(B134) No. 8 (+) — Chassis ground ( − − − − ):
Is the measured value less than the specified
value at except neutral position?
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?
4 CHECK NEUTRAL POSITION SWITCH.
Measure resistance between transmission har-
ness connector terminals.
Connector & terminal
(T9) No. 1 — No. 2:
Is the measured value less than the specified
value at except neutral position?
5 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
1) Disconnect connector from ECM.
2) Measure resistance of harness between
ECM and transmission harness connector.
Connector & terminal
(B134) No. 8 — (B128) No. 1:
Is the measured value less than the speci-
fied value?
6 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure resistance of harness between trans-
mission harness connector and engine ground.
Connector & terminal
(B128) No. 2 — Engine ground:
Is the measured value less than the specified
value?
Value
5 V
1 V
There is poor contact.
1 Ω
1 Ω
5 Ω
EN(H4DOSTC)-179
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Go to step 4.
Go to step 3. Go to step 5.
Repair poor con- Contact SUBARU
tact in ECM con- distributor service.
nector.
NOTE:
Inspection by DTM
is required,
cause
cause is deteriora-
tion of
parts.
Go to step 5. Repair open circuit
in transmission
harness or replace
neutral position
switch.
Go to step 6. Repair open circuit
in harness
between ECM and
transmission har-
ness connector.
Go to step 7. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
transmission har-
ness connector
and engine
grounding terminal
• Poor contact in
coupling connector
No
be-
probable
multiple