Subaru 2002 IMPREZA Service Manual page 917

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INTAKE AIR TEMPERATURE SEN-
SOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from intake air
temperature sensor.
3)Measure the resistance between intake air
temperature sensor terminals.
Terminals
No. 2 — No. 3:
2 CHECK INTAKE AIR TEMPERATURE SEN-
SOR.
Measure the resistance between intake air
temperature sensor terminals.
Terminals
No. 2 — No. 3:
3 CHECK HARNESS BETWEEN ECM AND IN-
TAKE AIR TEMPERATURE SENSOR CON-
NECTOR.
1)Disconnect the connector from ECM.
2)Measure the resistance of harness connec-
tor between ECM and intake air temperature
sensor connector.
Connector & terminal
(B136) No. 15 — (E20) No. 3:
4 CHECK HARNESS BETWEEN ECM AND IN-
TAKE AIR TEMPERATURE SENSOR CON-
NECTOR.
Measure the resistance of harness connector
between ECM and intake air temperature sen-
sor connector.
Connector & terminal
(B136) No. 13 — (E20) No. 2:
5 CHECK HARNESS BETWEEN ECM AND IN-
TAKE AIR TEMPERATURE SENSOR CON-
NECTOR.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B136) No. 15 — Chassis ground:
6 CHECK HARNESS BETWEEN ECM AND IN-
TAKE AIR TEMPERATURE SENSOR CON-
NECTOR.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B136) No. 13 — Chassis ground:
Check
Is the resistance between 2
and 3 kΩ at 20°C (68°F)?
Is the resistance between 0.66
and 1 kΩ at 50°C (122°F)?
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the resistance more than 1
MΩ?
EN(w/oOBD)-83
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Replace the intake
air temperature
sensor. <Ref. to
FU(w/oOBD)-38,
Intake Air Temper-
ature and Pres-
sure Sensor.>
Go to step 3. Replace the intake
air temperature
sensor. <Ref. to
FU(w/oOBD)-38,
Intake Air Temper-
ature and Pres-
sure Sensor.>
Go to step 4. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and intake
air temperature
and pressure sen-
sor connector
• Poor contact in
coupling connector
(B21)
Go to step 5. Repair the har-
ness and connec-
tor.
Go to step 6. Repair the ground
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connector.
Go to step 7. Repair the ground
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connector.
No