Subaru Legacy 2003 Service Manual page 532

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.
Does the measured value exceed the spec-
ified 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 HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from throttle position
sensor.
3) Measure resistance of harness between
throttle position sensor connector and
engine ground.
Connector & terminal
(E13) No. 2 — Engine ground:
Is the measured value less than the speci-
fied value?
3 CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1) Turn ignition switch to ON.
2) Measure voltage between throttle position
sensor connector and engine ground.
Connector & terminal
(E13) No. 3 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
Value
4.9 V
5 Ω
4.9 V
EN(H4SO)-135
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 3. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
throttle position
sensor and ECM
connector
• Poor contact in
coupling connector
• Poor contact in
joint connector
Repair battery Replace throttle
short circuit in har- position sensor.
ness between <Ref. to
throttle position FU(H4SO)-30,
sensor and ECM Throttle Position
connector. After Sensor.>
repair, replace
ECM. <Ref. to
FU(H4SO)-45,
Engine Control
Module.>
No