Subaru 2002 IMPREZA Service Manual page 571

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 HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from throttle posi-
tion sensor.
3)Measure the resistance of harness between
throttle position sensor connector and engine
ground.
Connector & terminal
(E13) No. 2 — Engine ground:
3 CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1)Turn the ignition switch to ON.
2)Measure the voltage between throttle posi-
tion sensor connector and engine ground.
Connector & terminal
(E13) No. 3 (+) — Engine ground ( − − − − ):
Check
Is the value more than 4.9 V?
Is the resistance less than 5
Ω?
Is the voltage more than 4.9 V? Repair the battery
EN-139
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 har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
throttle position
sensor and ECM
connector
• Poor contact in
coupling connector
(B21)
• Poor contact in
joint connector
(B83) or (B122)
Replace the throt-
short circuit in har- tle position sensor.
ness between <Ref. to FU-35,
throttle position Throttle Position
sensor and ECM Sensor.>
connector. After
repair, replace the
ECM. <Ref. to FU-
51, Engine Con-
trol Module.>
No