Subaru Impreza 2003 Service Manual page 638

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OTHER DTC ON DISPLAY.
2 CHECK INPUT SIGNAL FOR ECM.
1)Turn the ignition switch to ON.
2)Measure the voltage between ECM and
chassis ground in select lever "N" and "P"
ranges.
Connector & terminal
(B136) No. 21 (+) — Chassis ground ( − − − − ):
3 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM and chas-
sis ground in select lever except for "N" and "P"
ranges.
Connector & terminal
(B136) No. 21 (+) — Chassis ground ( − − − − ):
4 CHECK POOR CONTACT.
Check poor contact in ECM connector.
5 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 21 (+) — Chassis ground ( − − − − ):
6 CHECK HARNESS BETWEEN ECM AND IN-
HIBITOR SWITCH CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connectors from ECM and
inhibitor switch.
3)Measure the resistance of harness between
ECM and inhibitor switch connector.
Connector & terminal
(B136) No. 21 — (T7) No. 12:
Check
Is any other DTC displayed?
Is the voltage less than 1 V?
Is the voltage 4.5 — 5.5 V?
Is there poor contact in ECM
connector?
Is the voltage more than 10 V? Repair battery
Is the resistance less than 1
Ω?
EN(H4SO)-226
Yes
Inspect DTC using Go to step 2.
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4SO)-73, List
of Diagnostic
Trouble Code
(DTC).>
Go to step 3. Go to step 5.
Go to step 4. Go to step 5.
Repair poor con- Contact with SUB-
tact in ECM con- ARU distributor
nector. service.
NOTE:
Inspection by DTM
is required,
cause
cause is deteriora-
tion of
parts.
Go to step 6.
short circuit in har-
ness between
ECM and inhibitor
switch connector.
Go to step 7. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and inhibitor
switch connector
• Poor contact in
coupling connector
• Poor contact in
inhibitor switch
connector
• Poor contact in
ECM connector
No
be-
probable
multiple