Subaru 2009 IMPREZA, Service Manual

Page: 2760 / 3619

AC(diag)-31
Diagnostic Procedure for Sensors
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Step Check Yes No
1 CHECK IN-VEHICLE SENSOR.
1) Turn the ignition switch to OFF.
2) Remove the driver’s side lower cover.
3) Disconnect the connector from in-vehicle
sensor.
4) Measure the resistance between terminals
of in-vehicle sensor.
Terminals
No. 1 — No. 2:
Is the resistance approximately
2.2 k
:
at 25°C (77°F)?
Go to step 2 . Replace the in-
vehicle sensor.
<Ref. to AC-43,
REMOVAL, In-
Vehicle Sensor
(Auto A/C Model).>
2 CHECK INPUT SIGNAL FOR IN-VEHICLE
SENSOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between in-vehicle
sensor harness connector terminals.
Connector & terminal
(i55) No. 2 (+) — No. 1 (–):
Is the voltage approx. 5 V? Go to step 6 . Go to step 3 .
3 CHECK AUTO A/C CONTROL MODULE
OUTPUT SIGNAL.
1) Turn the ignition switch to OFF.
2) Remove the auto A/C control module.
3) Turn the ignition switch to ON.
4) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i88) No. 17 (+) — (i88) No. 14 (–):
Is the voltage approx. 5 V? Go to step 4 . Go to step 6 .
4 CHECK HARNESS BETWEEN AUTO A/C
CONTROL MODULE AND IN-VEHICLE SEN-
SOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the auto A/C
control module.
3) Measure the resistance of harness between
auto A/C control module and in-vehicle sensor.
Connector & terminal
(i55) No. 2 — (i88) No. 17:
Is the resistance less than 1
:
? Go to step 5 . Repair the harness
between auto A/C
control module and
in-vehicle sensor.
5 CHECK HARNESS BETWEEN AUTO A/C
CONTROL MODULE AND IN-VEHICLE SEN-
SOR.
Measure the resistance of harness between
auto A/C control module and in-vehicle sensor.
Connector & terminal
(i55) No. 1 — (i88) No. 14:
Is the resistance less than 1
:
? Go to step 6 . Repair the harness
between auto A/C
control module and
in-vehicle sensor.
6 CHECK POOR CONTACT.
Check poor contact of auto A/C control module
connector.
Is there poor contact of connec-
tor? Repair the connec-
tor. Replace the auto
A/C control mod-
ule. <Ref. to AC-
33, REMOVAL,
Control Unit (Auto
A/C Model).>