Subaru Impreza 2002 Service Manual page 3242

DIAGNOSTIC PROCEDURE FOR ACTUATORS
Step
1 CHECK POWER SUPPLY FOR AUTO A/C
CONTROL MODULE SIDE.
1)Turn the ignition switch ON.
2)Turn the A/C switch ON.
3)Measure the voltage between auto A/C con-
trol module harness connector terminal and
chassis ground.
Connector & terminal
(B283) No. 5 (+) — Chassis ground ( − − − − ):
2 CHECK POWER SUPPLY FOR ACTUATOR
SIDE.
Measure the voltage between air mix door
actuator harness connector terminal and chas-
sis ground.
Connector & terminal
(B293) No. 1 (+) — Chassis ground ( − − − − ):
3 CHECK SIGNAL FOR AUTO A/C CONTROL
MODULE SIDE.
Measure the voltage between auto A/C control
module harness connector terminal and chas-
sis ground with oscilloscope.
Connector & terminal
(B282) No. 4 (+) — Chassis ground ( − − − − ):
4 CHECK SIGNAL FOR ACTUATOR SIDE.
Measure the voltage between air mix door
actuator harness connector terminal and chas-
sis ground with oscilloscope.
Connector & terminal
(B293) No. 3 (+) — Chassis ground ( − − − − ):
5 CHECK GROUND CIRCUIT OF ACTUATOR.
1)Turn the ignition switch and A/C switch OFF.
2)Measure the resistance between air mix door
actuator harness connector terminal and chas-
sis ground.
Connector & terminal
(B293) No. 2 — Chassis ground:
6 CHECK POOR CONTACT.
Check poor contact in auto A/C control module
and air mix door actuator.
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Check
Is the voltage more than 10V? Go to step 2.
Is the voltage more than 10V? Go to step 3.
Is the voltage approx. 5.5V?
Is the voltage approx. 5.5V?
Is the resistance less than 1
Ω?
Is there poor contact?
AC-37
Yes
Replace the auto
A/C control mod-
ule.
Repair the open
circuit in harness
between auto A/C
control module
and air mix door
cutuator.
Go to step 4. Replace the auto
A/C control mod-
ule.
Go to step 5. Repair the open
circuit in harness
between auto A/C
control module
and air mix door
actuator.
Go to step 6. Repair the open
circuit in harness
between air mix
door actuator and
chassis ground.
Repair the poor Contact with your
contact. Subaru distributor
service.
No