air condition AUDI A4 2001 B5 / 1.G Technical Features Design And Function

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Important:
Note
New

Contents
It is not intended as a workshop manual.
The self-study programme will provide you with information on
design and functions.
For maintenance and repair operations it is essential that you
refer to the current technical literature.
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Engine and gearbox
Running gear
Axles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Mechanical unit mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Brake assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
CAN BUS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Steering column switch module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Function circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Control unit for vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Function circuit diagram for "lowline" version . . . . . . . . . . . . . . . . . . . . . 50
Function circuit diagram for "highline" version . . . . . . . . . . . . . . . . . . . . 52
Convenience system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Anti-theft alarm system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Radio - chorus II, concert II and symphony II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Navigation IV and Navigation Plus-D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Multi-communication bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Electric logbook "Audi Logbook" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Heater/AC
Design and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7-piston compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Glove compartment cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Solar roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fresh air blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Actuators/sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Functional diagram for fully automatic air conditioner . . . . . . . . . . . . . . 84
Additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 2.0 l R4 and 3.0 l V6 engines (see SSP 255) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Innovations - 2.5 l V6 TDI engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Innovations - automatic gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Electrical system

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High safety standards
With a thoroughly optimised body design and
comprehensive safety equipment, the new
Audi A4 is able to comply with all current valid
safety standards, throughout the world.
Crash sensors for the front airbags integrated
directly into the bumper bar, improve occu-
pant protection.
Finely-tuned aerodynamics
Despite the greater frontal area and the cool-
ing air current for the air conditioner (stand-
ard), it was possible to improve the C
D

value
by 5 %, in comparison to its predecessor,
to 0.28.
A special feature is the so-called aero-floor,
which provides for optimal airflow on the
underside of the vehicle.
Communication centre on wheels
With regard to infotainment, the new
Audi A4 leaves nothing to be desired.
4 different audio systems, 2 differently config-
ured Navigation systems and a car phone
with voice operation are on offer.
Electronic stability programme (ESP)
including brake assistant
For the latest ESP generation, the hydraulic
brake assistant is an integral part of the
standard equipment.
It is intended to assist the driver by automati-
cally increasing the brake pressure during
emergency braking.
SSP254_048

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CAN data bus
The Audi A4 is equipped with a widely
extended CAN data bus system.
Due to the ever increasing number of control
units installed in the vehicle and the associ-
ated requirement for data exchange, the
importance of the CAN data bus system
increases significantly.For communication between the
installed control units and the diagnos-
tic tester, two diagnosis wires (K and L)
are available.
The newly developed adapter VAS 6017 ena-
bles communication with all control units.
Drive BUS 500 kBaud
Convenience BUS 100 kBaud
Display BUS 100 kBaud
Diagnosis connection
K wire
Diagnosis connection
L wire (2nd K wire)
J402 Control unit for operating electronics,
navigation, TV tuner
J446 Control unit for parking aid
J453 Control unit for multi-function
steering wheel
J499 Control unit for telematics
J502 Control unit for tyre pressure monitor
J507 Control unit for speech entry
J519 Control unit for vehicle electrical
system
J526 Control unit for telephone -
permanent installation
J527 Control unit for steering column
electronics
R Radio
R94 Interface for navigation
R99 Chip card reader G85 Steering angle sender
E87 Operating and display unit for
air conditioner
J104 Control unit for ESP
J136 Control unit for seat adjustment with
memory, optional
J162 Auxiliary heater, optional
J217 Control unit for automatic gearbox
J220 Control unit for motronic
J234 Airbag control unit
J285 Control unit with display unit in
dash panel insert
J345 Control unit for trailer recognition
J386 Door control unit, driver’s side
J387 Door control unit, passenger side
J388 Rear left door control unit, optional
J389 Rear right door control unit, optional
J393 Central control unit for convenience
system
J401 Navigation system control unit
SSP254_112

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Heater/AC
Operating and display unit E87.
The redesigned system is based on the
performance data for top of the medium
range vehicles, taking account of low system
weight and energy consumption as well as, to
an increasing extent, recycling capability.
The operating and display unit E87 is
connected to the convenience CAN bus.
Diagnosis takes place via the K-wire.
Design and function
The air conditioner represents a further devel-
opment of the two-zone air conditioning
concept previously used in the A6.
Innovations include:
– Individual temperature control for both
driver and front passenger
– Option of synchronising the temperature
zones for driver and front passenger by
pressing the ”Auto” button for approx.
three seconds.
Example:
If the same temperature is desired for the
passenger’s side as for the driver’s side,
the ”Auto” button should be pressed for at
least three seconds.
The same applies the other way round, for
making the driver’s side temperature the
same as that of the passenger’s side.
– The fault diagnosis and measured value
blocks for the seat heating system are read
out via address word 08 for the air condi-
tioner.
– The system is encoded automatically via
the dash panel insert.– Integrated rotary control knob with poten-
tiometer for seat heating.
(this means the potentiometers cannot be
replaced individually)
– Intake blower V42 for passenger compart-
ment temperature sensor G56 is integrated
and cannot be replaced individually.
A distinction is made between eight different
versions, identified by means of the part
number index:
– with or without seat heating
– with or without navigation system,
– at a later date, with or without air quality
sensor.

SSP254_032

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Air conditioner
Heater/AC
Defrost
flaps
Flaps for
centre ventDefrost flap control
motor V107
Temperature
flap (upper)
Left temperature
flap control
motor V158Right tempera-
ture flap control
motor V159
Temperature
flap (lower)
Flaps for footwell
ventFootwell vent tempera-
ture sender (left) G261Footwell vent tempera-
ture sender (right) G262
Sender for outlet
temperature,
evaporator G263 Central flap
control motor V70
Temperature
sensor - fresh air
intake channel G89
Fresh air/air-
flow flap
Air recirculation
flap control
motor V113
Motor for air flow
flap V71
Recircula-
ted-air flap
Vent temperature
sender
left right
G150 G151
SSP254_019

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The basic functions of the air conditioner in
the Audi A4 are based on the Audi A6 system
and includes the following features:
– Air-side separation for driver’s and passen-
ger’s side.
– The heat exchanger can be replaced with-
out removing the air conditioner.
– The PTC additional heater element for die-
sel mechanical units can also be replaced
without removing the unit.
– All control motors and potentiometers are
easily accessible and replaceable.
– Connecting hose from air conditioner to
glove compartment for supplying the glove
compartment cooler (optional).
(in vehicles without glove compartment
cooling, the connection is sealed with a
rubber plug).
– Modified fresh air blower for passenger
compartment (description, see section:
Fresh air blower/electronically controlled
fresh air blower, on page 81).
Connecting hose to glove
compartment cooler
Glove compartment cooling
The cooler fills the entire space of the glove
compartment. It can, for instance, hold two
bottles with a volume of 0.25 and 0.7 litres.
The cold air supply is achieved via a connect-
ing hose from the air conditioner unit.
The hose is fitted with a rotary slide for cold
air regulation.
Two examples give an impression of its per-
formance:
– Cooling of the cooler contents from
approx. +30 °C to approx. +16 °C within one
hour and
– after switching off the cold air supply,
warming up by approx. +4 °C per hour at an
ambient temperature of approx.
+30 seconds and exposure to the sun.
Rotary valve
SSP254_015
SSP254_034

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Heater/AC
Significant advantages in comparison with
vehicles without solar roof are:
– lowered temperature level in vehicles
parked in the sun (see chart),
– increased efficiency of the air conditioner
as the interior temperature set is achieved
more quickly,
– despite the reduced output of the system
during the winter, an air-drying effect
occurs which effectively dehumidifies the
vehicle, reducing fogging of the windows.
Solar roof
For the first time, the A4 can optionally be
equipped with the solar roof previously used
in the A8 and A6.
The fresh air blower is continually driven by
electricity obtained from solar radiation.
The output is proportional to the intensity of
the sunlight.
Modifications to the familiar models:
– Re-engineered fresh air blower
– The DC/DC transformer has been discontin-
ued, its function is now performed by the
fresh air blower control unit J126.
Time [min]
Temperature [°C]
Radiation [W/m

2

]
Ventilation
Air conditioner
with control
systemSolar generator
SSP254_035
SSP254_036

Contacts
Heating without solar
Heating with solar
Global radiation

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Actuators/sensors
Heater/AC
Ambient temperature sensor
G17
Dash panel temperature
sensor G56
and
Temperature selection in the air condi-
tioner operating and display unit E87
Sender for footwell vent temperature,
right, G262
Sender for footwell vent tempera-
ture, left, G261
High-pressure sender G65 Evaporator outlet temperature
sender G263 Fresh air intake temperature
sensor G89
Sunlight penetration photo-
sensor G107
Signals:
Terminal 31b from automatic wash/wipe interval system
Regulating valve for air conditioner compressor N280
Air quality sensor G238 Vent temperature sender, right, G151
Vent temperature sender, left, G150
E
C
O
NO
F
F

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153.95244km9:3628.07.2000
Diagnosis connection
Radiator fan control unit J293
Radiator fan V7
Regulating valve for air con-
ditioner compressor N280
Central flap control motor V70 and
potentiometer G112 Control unit
for air conditioner Automatic gearbox
control unit J217
Motronic control unit J220
Defrost flap control motor V107 with
potentiometer G135
Motor for air flow flap V71 with
potentiometer G113
Temperature flap positioning motor V158
(right) with potentiometer G221
Series resistor for fresh air blower N24,
control unit for fresh air blower J126 with
fresh air blower V2
Signals:
ECON signal
Engine speed increase
Air conditioner compressor Control unit with display in dash
panel insert J285
Diagnosis interface for data bus
J533 (gateway)
Air recirculation flap control motor V113
for potentiometer G143
Temperature flap control motor V158
(left) with potentiometer G220

SSP254_041

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Heater/AC
Functional diagram
for fully automatic air
conditioner
Components
C20 Solar cells
E87 Operating and display unit for
air conditioner
G59 Driver’s seat temperature sensor
G60 Front passenger’s seat temperature
sensor
G65 High-pressure sender
G89 Temperature sensor - fresh air intake-
channel
G107 Sunlight penetration photosensor
G112 Potentiometer in positioning motor
for central flap
G113 Potentiometer in positioning motor
for air flow flap
G135 Potentiometer in central flap control
motor defrost flap
G143 Potentiometer in central flap control
motor recirculated-air flap
G150 Vent temperature sender, left
G151 Vent temperature sender, right
G220 Potentiometer, positioning motor for
temperature flap, left
G221 Potentiometer, positioning motor for
temperature flap, right
G238 Air quality sensor
G262 Vent temperature sender, footwell,
left
G262 Vent temperature sender, footwell,
right
G263 Vent temperature sender, evaporator
J9 Relay for heated windscreen and
rear window
J126 Blower control unit
N280 Regulating valve for compressor,
air conditioner
S Fuses
V2 Fresh air blower
V70 Central flap control motor
V71 Air flow flap control motor
V107 Defrost flap control motor
V113 Air recirculation flap control motor
V158 Temperature flap positioning motor,
left
V159 Temperature flap positioning motor,
right
1
2
3
4CAN-high convenience
CAN-low convenience
Terminal 75
Windscreen heating Z2
K-diagnostic connection
CAN-H CONVENIENCE
CAN-L CONVENIENCEConnection to
convenience data
bus
Colour coding
= Input signal
= Output signal
= Positive power supply
= Earth
= CAN-BUS

Auxiliary signals
Z1 Heated rear window
Z6 Heated driver’s seat
Z8 Heated front passenger’s seat
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