Subaru Legacy 2002 Service Manual page 648

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
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.
NOTE:
¼ Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN-34, Subaru Select Monitor.>
¼ 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
(B136) No. 15 (+) — Chassis ground
(−):
3 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 15 (+) — Chassis ground
(−):
4 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 17 (+) — Chassis ground
(−):
5 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR.)
Measure voltage between ECM connector
and chassis ground.
Step
Is the value less than 0.1
V?
Is the voltage more than
4.5 V?
Does the voltage change
more than 4.5 V by shaking
harness and connector of
ECM while monitoring the
value with voltage meter?
Is the voltage less than 0.1
V?
Does the voltage change
more than 0.1 V by shaking
harness and connector of
ECM while monitoring the
value with Subaru Select
Monitor?
EN-131
Check Yes
Go to step 2.
Go to step 4.
Repair poor con-
tact in ECM con-
nector.
Go to step 6.
Repair poor con-
tact in ECM con-
nector.
Engine (Diagnostics)
No
Even if MIL lights
up, the circuit has
returned to a nor-
mal condition at
this time. A tem-
porary poor con-
tact of the con-
nector may be the
cause.
NOTE:
In this case,
repair the follow-
ing:
¼ Poor contact in
throttle position
sensor connector
¼ Poor contact in
ECM connector
¼ Poor contact in
coupling connec-
tor (B21)
Go to step 3.
Contact with your
Subaru distributor
service.
NOTE:
Inspection by
DTM is required,
because probable
cause is deterio-
ration of multiple
parts.
Go to step 5.
Go to step 6.