Subaru Legacy 2003 Service Manual page 1944

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of throttle position sensor
signal using Subaru Select Monitor.
Is the measured value less than the speci-
fied value?
NOTE:
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4DOSTC)-26, Subaru Select Monitor.>
2 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground while throttle valve is fully
closed.
Connector & terminal
(B135) No. 9 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value?
3 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 9 (+) — Chassis ground ( − − − − ):
Does the measured value change by shaking
harness and connector of ECM while monitor-
ing the value with voltage meter?
4 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 7 (+) — Chassis ground ( − − − − ):
Is the measured value less than the specified
value?
5 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR.)
Measure the voltage between ECM connector
and chassis ground.
Does the measured value change by shaking
harness and connector of ECM while monitor-
ing the value with Subaru Select Monitor?
Value
0.1 V
4.5 V
The voltage changes.
0.1 V
The value changes.
EN(H4DOSTC)-105
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Even if MI lights
up, the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector
may be the cause.
NOTE:
In this case, repair
the following:
• Poor contact in
throttle position
sensor connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
Go to step 4. Go to step 3.
Repair the poor Contact SUBARU
contact in ECM distributor service.
connector.
NOTE:
Inspection by DTM
is required,
cause
cause is deteriora-
tion of
parts.
Go to step 6. Go to step 5.
Repair the poor Go to step 6.
contact in ECM
connector.
No
be-
probable
multiple