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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
♦ The position of the back pressure door -A- is visible via the air
intake opening in the plenum chamber when the recirculation
door -E- is open (if necessary, remove plenum chamber cover
and cover over fresh air intake. Refer to
⇒ “5.12 Fresh Air Intake Cover“, page 142
♦ For back pressure regulation (currently only intended on ve‐
hicles with A/C system), the fresh air intake channel is partially
closed via the back pressure door -A- at high speeds (from
approximately 80 km/h) by the Climatronic control module -
J255- (position of recirculation door -E- is specified by the
Climatronic control module).
♦ To reduce the change in noise from the fresh air blower -V2-
due to different air intake when switching from fresh air to
recirculation or vice versa, the airflow door motor -V71- and
recirculation door motor -V113- are activated as follows:
– When switching from fresh air to recirculation mode, the re‐
circulation door -E- is first opened, then the fresh air intake
channel is closed via the back pressure/fresh air door -A-.
– When switching from recirculation to fresh air mode, the fresh
air intake channel is first closed by the back pressure/fresh air
door -A-, then the recirculation door -E- is closed.
– In partial recirculation mode (currently only intended on vehi‐
cles with A/C system), the recirculation door -E- is opened and
the back pressure/fresh air door -A- is brought into a center
position by the Climatronic control module (fresh air and re‐
circulation air channel are simultaneously opened slightly).
This achieves improved cool-off in certain temperature ranges
and simultaneously draws in a certain portion of fresh air as
well.
♦ Airflow door motor -V71- , removing and installing, refer to
⇒ “5.8.1 Air Flow Door Motor V71 “, page 126
.
2.11
Refrigerant Circuit, Servicing
HD = High-pressure end
ND = Low-pressure end
Audi TT 2007 ➤
Heating, Ventilation and Air Conditioning - Edition 01.2011
2. Description and Operation
63