Subaru Impreza 2003 Service Manual page 852

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR.
1)Disconnect the connector from ECM and
throttle position sensor.
2)Measure the 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:
2 CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR CONNEC-
TOR.
1)Disconnect the connector from TCM. (AT
model)
2)Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 17 — Chassis ground:
(B136) No. 15 — Chassis ground:
3 CHECK INPUT SIGNAL FOR ECM.
1)Connect the connector to ECM and throttle
position sensor.
2)Ignition the switch to ON.
3)Measure the voltage between ECM termi-
nals while throttle valve is fully closed.
Connector & terminal
(B136) No. 15 (+) — No. 17 ( − − − − ):
4 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM terminals
while throttle valve is fully opened.
Connector & terminal
(B136) No. 15 (+) — No. 17 ( − − − − ):
5 CHECK POOR CONTACT.
Check poor contact in throttle position sensor
connector.
6 CHECK CONDITION OF THROTTLE POSI-
TION SENSOR INSTALLATION.
Check
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the voltage less than 0.1 V? Go to step 5.
Is the voltage more than 4.5 V? Go to step 5.
Is there poor contact in throttle
position sensor connector?
Are the throttle position sensor
installing screw tightened
securely?
EN(H4SOw/oOBD)-76
Yes
Go to step 2. Repair the open
circuit between
ECM and throttle
position sensor.
Go to step 3. Repair the ground
short circuit
between ECM and
chassis ground.
Go to step 4.
Go to step 6.
Repair the poor Replace the throt-
contact in throttle tle position sensor.
position sensor
connector.
Replace the throt- Adjust the throttle
tle position sensor. position sensor
and tighten throt-
tle position sensor
installing screws
securely.
No