Subaru 2009 IMPREZA Service Manual page 2732

2. General Description
A: CAUTION
1) Never connect the battery in reverse polarity.
• Doing so may immediately damage the auto A/C
control module.
2) Do not disconnect the battery terminals while the
engine is running.
• A large counter electromotive force will be gener-
ated in the generator, and this voltage may damage
electronic parts such as auto A/C control module
etc.
3) Before disconnecting the connectors of sensors
and the auto A/C control module, be sure to turn off
the ignition switch.
• Auto A/C control module may be damaged.
4) Every A/C-related part is a precision part. Do not
drop them.
5) Airbag system wiring harness is routed near the
A/C control panel and junction box.
CAUTION:
• Do not use electrical test equipment on the
airbag system wiring harness and connector.
• Be careful not to damage the airbag system
wiring harness when servicing the A/C control
panel and junction box.
B: INSPECTION
Before performing the diagnosis, check the follow-
ing items which may cause problems in the A/C
system.
1. BATTERY
1) Measure the battery voltage and specific gravity
of the electrolyte.
Standard voltage:
12 V
Specific gravity:
1.260 or more
2) Check the condition of the fuses for A/C system
power supply and other fuses.
3) Check the condition of harness and harness
connector connections.
2. ASPIRATOR HOSE
1) Turn the ignition switch to ON, and press the
A/C switch.
2) Turn the temperature control dial to maximum
hot position.
3) Set the blow vents to the DEF position.
4) Turn the fan switch to "MAX" position.
General Description
5) Put a strip of paper close to the front side of in-
vehicle sensor suction port (A) located in the instru-
ment panel lower cover, and check that air is being
sucked into the port by seeing the paper moving to-
wards the port.
NOTE:
Be careful not to let the paper get sucked into the
port.
6) If the paper does not move at all, remove the in-
strument panel lower cover <Ref. to EI-46, RE-
MOVAL, Instrument Panel Lower Cover.> and
check for poor connection of the aspirator hose (A),
in-vehicle sensor and heater unit, and repair them if
necessary.
3. A/C LINE
Check the connection for A/C line (A) and lower
side high-pressure pipe.
4. CONTROL LINKAGE
1) Check the state of mode door linkage.
2) Check the state of air mix door linkage.
3) Check the state of FRESH/RECIRC door link-
age.
AC(diag)-3
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
(A)
(A)
AC-01714
AC-01869
(A) (A) (A)
AC-01878