Subaru Impreza 2004 Service Manual page 23

Step
8 CHECK POOR CONTACT.
Check poor contact in main fan motor connec-
tor.
9 CHECK MAIN FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 1 and 2 (DOHC turbo model) or No.2
(SOHC model), and negative (−) terminal to
terminal No. 3 and 4 (DOHC turbo model) or
No.1 (SOHC model).
10 CHECK OPERATION OF SUB FAN MOTOR.
Check the operation of sub fan motor.
11 CHECK POWER SUPPLY TO SUB FAN MO-
TOR.
CAUTION:
Be careful not to overheat the engine during
repair.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from sub fan
motor.
3)Start the engine, and warm it up until engine
coolant temperature increases over 100°C
(212°F).
4)Stop the engine and turn the ignition switch
to ON.
5)Measure the voltage between sub fan motor
connector and chassis ground.
Connector & terminal
DOHC Turbo model:
(F16) No. 1, 2 (+) — Chassis ground ( − − − − ):
SOHC model:
(F16) No. 2 (+) — Chassis ground ( − − − − ):
12 CHECK GROUND CIRCUIT OF SUB FAN
MOTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between sub fan
motor connector and chassis ground.
Connector & terminal
DOHC Turbo model:
(F16) No. 3, 4 — Chassis ground:
SOHC model:
(F16) No. 1 — Chassis ground:
13 CHECK POOR CONTACT.
Check poor contact in sub fan motor connec-
tor.
14 CHECK SUB FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 1 and 2 (DOHC turbo model) or No.2
(SOHC model), and negative (−) terminal to
terminal No. 3 and 4 (DOHC turbo model) or
No.1 (SOHC model).
15 CHECK EACH SENSOR AND POTENTIOME-
TER.
Check the sensors and potentiometer for
proper operation using the self-diagnostic
function. <Ref. to AC(diag)-9, Diagnostics
Chart for Self-diagnosis.>
Diagnostics for A/C System Malfunction
Is there poor contact in main
fan motor connector?
Does the main fan rotate?
Does the radiator sub fan oper-
ate?
Is the voltage more than 10 V? Go to step 12.
Is the resistance less than 1
Ω?
Is there poor contact in sub fan
motor connector?
Does the sub fan rotate?
Is the operation of each sensor
and potentiometer normal?
AC(diag)-21
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Check
Repair the poor
contact in main fan
motor connector.
Repair the poor
contact in main fan
motor connector.
Go to step 15.
Go to step 13.
Repair the poor
contact in sub fan
motor connector.
Repair the poor
contact in sub fan
motor connector.
Go to step 16.
Yes No
Go to step 9.
Replace the main
fan motor with a
new one.
Go to step 11.
Repair the open
circuit in harness
for power supply
circuit.
Repair the open
circuit in harness
between sub fan
motor connector
and chassis
ground.
Go to step 14.
Replace the sub
fan motor with a
new one.
Check the sensor
and circuit. <Ref.
to AC(diag)-29,
Diagnostic Proce-
dure for Sensors.>