Subaru LEGACY 2003 Service Manual page 82

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
1 CHECK CONDITION OF THROTTLE POSI-
TION SENSOR INSTALLATION.
Are the throttle position sensor installing screw
tightened securely?
2 CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR.
1) Disconnect connector from ECM and throt-
tle position sensor.
2) Measure resistance between ECM and
throttle position sensor.
Connector & terminal
(B136) No. 16 — (E13) No. 2:
(B136) No. 17 — (E13) No. 3:
(B136) No. 15 — (E13) No. 4:
Is the measured value less than the speci-
fied value?
3 CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR CONNEC-
TOR.
1) Disconnect connector from TCM. (AT vehi-
cle)
2) Measure resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 17 — Chassis ground:
(B136) No. 15 — Chassis ground:
Does the measured value exceed the spec-
ified value?
4 CHECK INPUT SIGNAL FOR ECM.
1) Connect connector to ECM and throttle
position sensor.
2) Ignition switch to ON.
3) Measure voltage between ECM terminals
while throttle valve is fully closed.
Connector & terminal
(B136) No. 17 — No. 15:
Is the measured value less than the speci-
fied value?
5 CHECK INPUT SIGNAL FROM ECM.
Measure voltage between ECM terminals
while throttle valve is fully opened.
Connector & terminal
(B136) No. 17 — No. 15:
Does the measured value exceed the specified
value?
6 CHECK POOR CONTACT.
Check poor contact in throttle position sensor
connector.
Is there poor contact in throttle position sensor
connector?
Step
EN(H4SOw/oOBD)-80
Value
Installing screw is securely
tightened.
1 Ω
1 MΩ
0.1 V
4.5 V
There is poor contact.
Yes
Go to step 2. Adjust throttle
position sensor
and tighten throt-
tle position sensor
installing screws
securely.
Go to step 3. Repair open circuit
between ECM and
throttle position
sensor.
Go to step 4. Repair ground
short circuit
between ECM and
chassis ground.
Go to step 6. Go to step 5.
Go to step 6. Replace ECM.
Repair poor con- Replace throttle
tact in throttle posi- position sensor.
tion sensor
connector.
No