Subaru 2002 IMPREZA Service Manual page 567

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK CURRENT DATA.
1)Start the engine.
2)Read the data of throttle position sensor sig-
nal using Subaru Select Monitor or OBD-II
general scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN-34, Subaru Select Monitor.>
•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 the 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 the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 15 (+) — Chassis ground ( − − − − ):
4 CHECK INPUT SIGNAL FOR ECM.
Measure the 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 the voltage between ECM connector
and chassis ground.
Check
Is the value less than 0.1 V?
Is the voltage more than 4.5 V? Go to step 4.
Does the voltage change more
than 4.5 V by shaking harness
and connector of ECM while
monitoring the value with volt-
age meter?
Is the voltage less than 0.1 V? Go to step 6.
Does the voltage change more
than 0.1 V by shaking harness
and connector of ECM while
monitoring the value with Sub-
aru Select Monitor?
EN-135
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Even if MIL 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
(B21)
Go to step 3.
Repair the poor Contact with your
contact in ECM Subaru distributor
connector. service.
NOTE:
Inspection by DTM
is required,
cause
cause is deteriora-
tion of
parts.
Go to step 5.
Repair the poor Go to step 6.
contact in ECM
connector.
No
be-
probable
multiple