Subaru Legacy 2003 Service Manual page 528

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK CURRENT DATA.
1) Start engine.
2) Read data of throttle position sensor signal
using Subaru Select Monitor or OBD-II gen-
eral scan tool.
Is the measured value less than the speci-
fied value?
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)-32, Subaru Select Moni-
tor.>
•OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
2 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector and
chassis ground while throttle valve is fully
closed.
Connector & terminal
(B135) No. 3 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value?
3 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector and
chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value by shaking harness and connector of
ECM while monitoring the value with voltage
meter?
4 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector and
chassis ground.
Connector & terminal
(B135) No. 13 (+) — Chassis ground ( − − − − ):
Is the measured value less than the specified
value?
5 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR.)
Measure voltage between ECM connector and
chassis ground.
Does the measured value exceed the specified
value by shaking harness and connector of
ECM while monitoring the value with Subaru
Select Monitor?
Value
0.1 V
4.5 V
4.5 V
0.1 V
0.1 V
EN(H4SO)-131
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 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 6. Go to step 5.
Repair poor con- Go to step 6.
tact in ECM con-
nector.
No
be-
probable
multiple