Audi Q7: A/C System Temperature Door Heat Output Activation, Checking
Note
- Depending on vehicle equipment, there are different versions
of the A/C system for the Audi Q7. Make sure to use the correct
version and pay attention to the allocation of different
components. Refer to
→ Chapter "A/C System Versions" and Parts Catalog.
- For vehicles with a "Low" A/C system, there is no Rear A/C
Display Control Head -E265-, no rear air distribution housing
and no rear heater and A/C unit installed.
- For vehicles with a "Mid" or "Mix" A/C system, a Rear A/C
Display Control Head -E265- version -A-
and a rear air distribution housing are installed (but no rear
heater and A/C unit). Refer to
→ Chapter "Rear A/C Display Control Head -E265-, Removing and
Installing, High A/C System".
- For vehicles with a "High" A/C system, a Rear A/C Display
Control Head -E265- version -B- and
a rear heater and A/C unit are installed. Refer to
→ Chapter "Rear A/C Display Control Head -E265-, Removing and
Installing, High A/C System".
- On a vehicle with a "Low" A/C system (without a Rear A/C
Display Control Head -E265-, without an air distribution housing
and a rear heater and A/C unit) the temperature of the air which
flows from the front heater and A/C unit to the rear vent is
regulated from the Front A/C Display Control Head -E87- so that
the air out of the vent for the front area has an average
temperature. The target temperature for the air from the vents
in the front area is calculated via the setting for the left and
right side on the Front A/C Display Control Head -E87- from the
Front A/C Display Control Head -E87-. However, if a setting
which no longer regulates the temperature (for example, "HI" for
maximum heating or "LO" for maximum cooling) is present on the
Front A/C Display Control Head -E87-, the temperature of the air
from the vents in the front area is no longer regulated. If, for
example, maximum heating "HI" is set on the Front A/C Display
Control Head -E87- for one side and maximum cooling "LO" for the
other side, the air for the vents in the front area is maximally
heated.
- On a vehicle with a "Mid" or "Mix" A/C system (with a
version -A-Rear A/C Display Control
Head -E265-, and an air distribution housing but without a rear
heater and A/C unit) the temperature of the air which flows from
the front heater and A/C unit to the rear air distribution
housing is regulated from the Front A/C Display Control Head
-E87- so that the air out of the vent for the front area has an
average temperature. The target temperature for the air from the
vents in the front area is calculated via the adjustment for the
left and right side on the Front A/C Display Control Head -E87-
and the adjustment Rear A/C Display Control Head -E265- from the
Front A/C Display Control Head -E87-. However, if a setting
which no longer regulates the temperature (for example, "HI" for
maximum heating or "LO" for maximum cooling) is present on the
Front A/C Display Control Head -E87-, the temperature of the air
from the vents in the front area is no longer regulated. If, for
example, maximum heating "HI" is set on the Front A/C Display
Control Head -E87- for one side and maximum cooling "LO" for the
other side depending on the adjustment on the Rear A/C Display
Control Head -E265- the air for the vents in the front area is
maximally heated or cooled.
- Certain A/C system functions can be switched on and off via
the MMI (Multi Media Interface) in the "A/C system" function
under the "Car"/"Vehicle" menu. The A/C system control can also
be influenced via the presets in the MMI (Multi Media Interface)
under the "A/C system" function in the "Car"/"Vehicle" menu.
Therefore, check the preset in the MMI first in the case there
is a problem with these components. Refer to Infotainment/MMI
Operating Instructions.
Special tools and workshop equipment
required
- Vehicle Diagnostic Tester with the "Guided Fault Finding"
function and the corresponding connection lines. Refer to
Workshop Equipment.
- A standard thermometer (for temperature measurement; if
necessary, a thermometer with two measuring probes for
simultaneous measurement, for example, for temperature on the
right and left)
If the coolant circuit is not completely bled after filling,
air may collect in the front heater and A/C unit heater core
(and the rear heater and A/C unit, if equipped), which reduces
the heat output. There may also be noise or the customer may
complain of different air temperatures flowing out of the vents
on the driver side and front passenger side (front and rear,
left and right rear) at the same setting.
Corrective Measure:
- Check the coolant circuit and bleed it again if necessary.
Refer to
→ Chapter "Coolant Circuit, Bleeding".
- If it is suspected that air remains in the cooling system
after the bleeding operation. Perform a lengthy test drive at
high engine speed (at least 10 minutes, engine speed above 2500
rpm). Select a low gear during the test to prevent excessive
vehicle speed.
In the event of a customer complaint regarding poor heating
output at certain engine speeds:
- Check the incorporation of the heat exchanger in the front
heater and A/C unit (and in the rear heater and A/C unit if
present) into the coolant circuit. If for example the two
coolant hoses (supply and return) of the engine are
interchanged, the coolant is flowing in the wrong direction
through the heater core. It is also possible that the Coolant
Recirculation Pump -V50- is working against the engine coolant
pump. Refer to
→ Chapter "Incorporating the Heating and A/C System in the
Coolant Circuit" and
→ Rep. Gr.19; Coolant System/Coolant; Connection Diagram -
Coolant Hoses.
If a different air temperature is coming out of the vents
during A/C system control mode, it may be caused by the
following.
- One or more temperature doors in the front heater and A/C
unit (or in the rear heater and A/C unit if present) does not
close completely or does not reach its end position.
- There is air in the front heater and A/C unit heater core
(of the rear heater and A/C unit). This results in fluctuating
flows through the affected heater core and the heat is not
distributed uniformly.
- When installing the heat exchanger the foam seal has
loosened and air may flow past the heat exchanger (refer to
→ Chapter "Heater Core, Removing and Installing")
(front heater and A/C unit) (and refer to
→ Chapter "Heater Core, Removing and Installing")
(heat exchanger in the rear heater and A/C unit).
- The A/C system refrigerant circuit is not filled with the
correct quantity of refrigerant (perform a cooling output test).
Refer to
→ Chapter "Cooling Output, Checking".
Note
- A start-stop system is available as optional equipment for
certain engines of this vehicle. Depending on the setting on the
Front A/C Display Control Head -E87- (or if present at the Rear
A/C Display Control Head -E265-) it can prevent the stop
function. If, for example, the "defrost" mode is selected on the
Front A/C Display Control Head -E87-, the stop function is not
possible or will be interrupted and the engine will start as
soon as this operating mode is selected. The same also applies
if the difference between the selected specified temperature and
the measured actual temperature exceeds a certain value in
heating and cooling mode. Refer to Vehicle Diagnostic Tester in
the "Guided Fault Finding" function.
- In vehicles with a start-stop system, the Coolant
Recirculation Pump -V50- (the Recirculation Pump -V55- of the
parking heater) is activated even when the stop function is
active in order to maintain the coolant flow through the heat
exchanger. Refer to
→ Chapter "Component Location Overview - Rear Components Outside
of Passenger Compartment". Refer to Vehicle
Diagnostic Tester in the "Guided Fault Finding" function.
Heater and A/C Unit, Removing and Installing
Special tools and workshop equipment
required
- Hose Clamps - Up To 25mm -3094- and Hose Clamps - Up To 40mm
-3093-
- Commercial compressed-air gun with rubber end piece
- Cooling System Tester -VAG1274B- (and corresponding
adapters)
Note
- Depending on vehicle equipment, there are different versions
of the A/C system for the Audi Q7. Make sure to use the correct
version and pay attention to the allocation of different
components. Refer to
→ Chapter "A/C System Versions" and Parts Catalog.
- When removing, record the bolt lengths and allocation for
the reinstallation.
- All cable ties and other wiring harness fasteners released
or cut open when removing the heater and A/C units are to be
re-attached in same position on installation.
Removing
- Turn off the ignition.
- Discharge the refrigerant circuit. Refer to
→ Refrigerant R134a Servicing; Rep. Gr.87; Refrigerant Circuit.
- Remove the plenum chamber cover. Refer to
→ Body Exterior; Rep. Gr.50; Bulkhead; Plenum Chamber Cover,
Removing and Installing.
- Remove the tower brace -A-.
Refer to
→ Suspension, Wheels, Steering; Rep. Gr.40; Suspension Strut and
Upper Control Arm; Tower Brace, Removing and Installing.
- Loosen the lower plenum chamber bulkhead
-B- from the vehicle and move to
the side (do not remove). Refer to
→ Body Exterior; Rep. Gr.50; Bulkhead; Overview - Bulkhead.
WARNING
There is a risk of scalding from hot steam and
coolant.
- The cooling system is under pressure when the engine
is warm.
- To reduce the pressure, cover the coolant reservoir
cap with cloths and then open it carefully.
- Carefully open the coolant expansion tank cap
-A- (do not completely remove).
Note
There are different versions of the coolant expansion tank
and in different allocations in the engine compartment. Refer to
→ Rep. Gr.19; Coolant System/Coolant; Coolant, Draining and
Filling.
- Label the arrangement of the coolant hoses at the
connections to the heater core -A-
(supply from the Coolant Recirculation Pump -V50-) and
-B- (return to the engine).
Note
- The heat exchanger is installed in the heater and A/C unit
so that a specific flow direction of the coolant is necessary
for clean bleeding of the heater core. Therefore, the coolant
hoses must be connected on the correct side. Refer to
→ Chapter "Incorporating the Heating and A/C System in the
Coolant Circuit".
- Bleed the coolant circuit. Refer to
→ Chapter "Coolant Circuit, Bleeding" and
→ Rep. Gr.19; Coolant System/Coolant; Coolant, Draining and
Filling.
Note
There are different versions of the coolant expansion tank
and in different allocations in the engine compartment. Refer to
→ Rep. Gr.19; Coolant System/Coolant; Coolant, Draining and
Filling.
- Label the arrangement of the coolant hoses at the
connections to the heater core -A-
(supply from the Coolant Recirculation Pump -V50-) and
-B- (return to the engine).
Note
- The heat exchanger is installed in the heater and A/C unit
so that a specific flow direction of the coolant is necessary
for clean bleeding of the heater core. Therefore, the coolant
hoses must be connected on the correct side. Refer to
→ Chapter "Incorporating the Heating and A/C System in the
Coolant Circuit".
- Bleed the coolant circuit. Refer to
→ Chapter "Coolant Circuit, Bleeding" and
→ Rep. Gr.19; Coolant System/Coolant; Coolant, Draining and
Filling.
- Clamp the coolant hoses -A and B-
with hose clamps -E-.
- Cover the area beneath connections for coolant hoses
-A and B-, for example with
absorbent paper.
- Place a small container under the connections for coolant
hoses -A and B- (to the heater
core).
Note
To prevent coolant from entering the plenum chamber when
removing coolant hoses -A and B-.
- Remove the coolant hoses -A and B-
from the connections to the heater and A/C unit heater core.
- Insert one section each of hose -A and
B- on to both connections to heater core.
- Place a container -B- under the
other end of the hose -C- .
- Using a compressed air gun -D-,
carefully blow coolant out of the heater core against the normal
flow direction of the coolant) via shaft
-A- into container -B-.
- Disconnect the refrigerant lines -A
and C- from the front expansion valve
-D- and put aside (do not remove).
Refer to
→ Chapter "Refrigerant Lines, Disconnecting from Front Expansion
Valve and Reconnecting".
Note
Immediately seal off any open line connections and
connection points with clean plugs, for example, taken from the
Engine Bung Set -VAS6122-.
- Loosen the grommet with the support ring
-D- from the plenum chamber rear
wall toward the passenger compartment (it is removed and
installed with the heater and A/C unit).
- Vehicles with a "Mid", "Mix" or "High" A/C system, remove
the rear heater and A/C unit. Refer to
→ Chapter "Heater and A/C Unit, Removing and Installing, High
A/C System".
- Remove the instrument panel central tube. Refer to
→ Body Interior; Rep. Gr.70; Instrument Panel Central Tube;
Instrument Panel Central Tube, Removing and Installing.
Caution
A/C system malfunctions in the case of interchanged
control motors and/or connectors. Refer to
→ Chapter "Main Wiring Diagram for A/C System Actuators".
- The adjustment motors and connectors are identical.
If they are installed or connected incorrectly, the
corresponding doors cannot be properly adapted and/or
activated.
- Clearly label the actuators and connectors prior to
removal to prevent incorrect installation.
- Vehicles with a "Low" A/C system, remove the rear air duct.
Refer to
→ Chapter "Air Ducts and Vents in the Rear Vehicle Interior, Low
A/C System".
- On vehicles with a Auxiliary Heater Control Module -J604-
with Auxiliary Heater Heating Element -Z35-, disconnect the
connector -A- and remove the
connections -C- (positive) and
-B-.
- Remove both condensation water drains
-A- from the connections -B-
on the heater and A/C unit.
Note
The "A/C system "wiring harness is removed with the heater
and A/C unit.
- Cover the floor covering in the area of the center tunnel
with a mat.
- Free up the wiring harness -F-.
- Remove the grommet -E- for the
coolant pipes to the heat exchanger and grommet
-D- for the expansion valve from
the openings in the rear wall of the plenum chamber and
carefully detach the heater and A/C unit
-C- (so that no components are damaged by any still
attached connections) slightly from the vehicle and remove it in
the direction of the front passenger footwell.
Installing
Install in reverse order of removal. Note the following:
Note
Before installing, check all gaskets and grommets on the
heater and A/C unit for damage and replace if necessary.
- Coat the grommet -B and C- with
grease and install it in the plenum chamber rear wall
-A-.
- Install the support ring -D- in
the grommet.
- Check the position of the coolant and refrigerant lines in
both grommets in the plenum chamber rear wall, and if necessary,
align the heater and A/C unit so that the lines are not
tensioned in the grommets.
Note
When installing air ducts ensure proper seating and
leak-proof connection of the components. If the connection
points are not leak-proof, noises can result from escaping air
or the escaping warm or cold air can affect the regulation of
the A/C system.
- Remove the refrigerant line from the front expansion valve.
Refer to
→ Chapter "Refrigerant Lines, Disconnecting from Front Expansion
Valve and Reconnecting".
- Install both coolant hoses -A and B-
on the coolant pipes to the heater core in the front heater and
A/C unit bleed the coolant circuit as described with the engine
off, and check for leaks. Refer to
→ Chapter "Heater Core, Removing and Installing" and
→ Chapter "Heater Core, Removing and Installing".
- Bleed the heat exchanger in the heater and A/C unit. Refer
to
→ Chapter "Heater Core, Removing and Installing" and
→ Chapter "Heater Core, Removing and Installing".
Note
When installing the instrument panel, make sure that the
"defrost" intermediate piece its properly on heater and A/C unit
and the defroster vent does not pinch the intermediate piece.
Refer to
→ Chapter "Overview - Air Routing and Air Distribution in
Passenger Compartment, Front".
- Evacuate and charge the refrigerant circuit. Refer to
→ Refrigerant R134a Servicing; Rep. Gr.87; Refrigerant Circuit.
- Perform the basic setting and the output diagnostic test
mode of the A/C system. Refer to Vehicle Diagnostic Tester in
the "Guided Fault Finding" function.
Note
- In this vehicle, the actuators are equipped with
electronics. During the basic setting, a new control motor
learns its position on the heater and A/C unit and can then be
activated by the Front A/C Display Control Head -E87- (currently
all actuators are identical). Refer to Vehicle Diagnostic Tester
in the "Guided Fault Finding" function.
- During the basic setting, the actuators are assigned and
adapted corresponding to the switching sequence of the wiring.
If this sequence does not conform with the specification, the
actuators will adapt incorrectly and the door control will be
wrong. Refer to
→ Chapter "Main Wiring Diagram for A/C System Actuators".
- Check the DTC memory on the Front A/C Display Control Head
-E87- and erase any displayed malfunctions. Refer to Vehicle
Diagnostic Tester in the "Guided Fault Finding" function.
- Operate the A/C system after charging the refrigerant
circuit. Refer to
→ Chapter "A/C System, Starting after Charging Refrigerant
Circuit".
Note
Note the information regarding operating the A/C system
after filling. Refer to
→ Refrigerant R134a Servicing; Rep. Gr.87; A/C System, General
Information.
READ NEXT:
- Turn off the ignition.
- Discharge the refrigerant circuit. Refer to
→ Refrigerant R134a Servicing; Rep. Gr.87; Refrigerant Circuit.
- Remove the front heater and A/C
Heater Core, Preparing for Removal
- Turn on the ignition.
- Adjust the airflow direction of the air on the Front A/C
Display Control Head -E87- to "DEF" (to the windshield).
- Set the
Removing
- Turn off the ignition.
- Remove the glove compartment (for the right condensation
water drain). Refer to
→ Body Interior; Rep. Gr.68; Storage Compartments and C
SEE MORE:
Subframe
Caution
There is a risk of damaging the threads on the subframe
threaded connection to the body.
The subframe bolts on the body must not be loosened or
tightened with an impact wrench.
Always install all bolts by hand for the first few turns.
1 - Bolt
20 Nm
2&nb
Information on the Refrigerant Lines and A/C Compressor
Caution
Danger due to refrigerant coming out under pressure.
Danger of frost bite to skin and other parts of the
body.
Only loosen the connection point bolts when the
refrigerant circuit is empty.
Note
On most vehicles the