Audi A6 2005 - Electrics Manual

326
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Subject to
technical change.
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AUDI AG
I/VK 35
Service.t[email protected]
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AUDI AG
D 85045 Ingolstadt
Technical release 01/04
Printed in Germany
A04.5S00.09.20
Audi A6 ‘05 – Electrics
Self-Study Programme 326
Vorsprung durch Technik www.audi.co.uk Service Training

The new Audi A6 – the most progressive vehicle
takes the lead.
The new Audi A6 consistently adopts the highly
networked electronic architecture, which is already
used in the Audi A8. Overall, new technologies allow
the A6 to match up with its "model" vehicle, the Audi
A8. Features, which were previously reserved or
luxury vehicles, are now also available in the top-
class segment.
In combination with these diverse capabilities,
the underlying technology has, o course,
been enhanced considerably.
The use o the most modern network technologies,
such as CAN, LIN, MOST and Bluetooth, and the
related distributed vehicle unctions signals the
arrival o a new generation o vehicle electrics in
this class.
Some o these are sa ety-related eatures, such as
the combined rain/light sensor or the pivoting
cornering headlight. Com ort eatures o the top
class, such as the MMI operating system or
sophisticated unctionalities or the mobile
baseplate, which is available ex-works, are part and
parcel o these new saloons.
The new Audi A6 has everything that is needed to
become the Number One model in the top-class
range.
It combines many di erent, attractive components
to orm one unit. Design and per ormance go
hand-in-hand. The new Audi A6 will take over
as the most progressive vehicle.
The Audi A6 – the most progressive vehicle takes the lead
Number One: With Design & Per ormance

NoteRe erence NoteRe erence
Control unit installation positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Bus topology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installation positions of fuses and relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Overview
Convenience electrics
Control unit for power management J644 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
ccess and start authorisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Immobiliser and component protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
External lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Control unit in dash panel insert J285 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Control unit for on-board power supply J519 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Control unit 2 for on-board power supply J520 . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Central control unit for convenience system J393 . . . . . . . . . . . . . . . . . . . . . . . . 55
Door control units J386 - J389 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Control units for seat adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Infotainment
Multimedia interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
ntenna systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Control unit for front information J523 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Sound systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
vailable telephone systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
The Sel -Study Programme provides in ormation on the undamentals o design and unction o new vehicle
models, new vehicle components or new technologies.
The Sel -Study Programme is not a Workshop Manual!
Speci ied values serve only to make the in ormation easier to understand and relate to the so tware version
that was valid at the time the Sel -Study Programme (SSP) was created.
For maintenance and repair work, please make sure to use the current technical documentation.
Contents

4
Overview
1 Auxiliary heating control unit J364
2 Control unit or ABS with EDL J104
3 Control unit or distance control J428
4 Transmitter unit in wheel well or tyre pressure
monitoring, ront le t G431
5 Control unit or on-board power supply J519
6 Door control unit, driver's side J386
7 Control unit or access and
start authorisation J518
8 Control unit in dash panel insert J285
9 Control unit or steering column electronics J527
10 Control unit or telephone, telematics J526
Telephone transmitter and receiver R36
11 Engine control unit J623
12 Climatronic control unit J255
13 Control unit or seat adjustment with steering-
column adjustment memory J136
14 Level control unit J197
Control unit or headlight range control J431
Control unit or tyre pressure monitoring J502
Control unit 2 or onboard power supply J520
Control unit or display and operating unit or
ront in ormation J523
Data bus diagnosis inter ace J533
Antenna read-in unit or keyless access
authorisation J723
15 CD changer R41
CD ROM drive R92
16 Door control unit, rear le t J388
17 Airbag control unit J234
Control unit installation positions

5
18 Rotation rate sensor 202
19 Door control unit, passenger's side J387
20 Control unit or seat adjustment with memory,
passenger’s side, J521
21 Door control unit, rear right J389
22 Transmitter unit in wheel well or tyre pressure
monitoring, rear le t G433
23 Radio receiver or auxiliary heating R64
24 Control unit or navigation with CD drive J401
Control unit or voice input J507
Digital sound package control unit J525
Radio R
TV tuner R78
Digital radio R147
25 Transmitter unit in wheel well or tyre pressure
monitoring, rear right G434
26 Parking aid control unit J446
Control unit or trailer detection J345
27 Central control unit or convenience system J393
28 Control unit or electric parking and
hand brake J540
29 Control unit or power management J644
326_146

6
Bus topology
Overview
NOX sensor
J583
Rotation rate sensor
G202
Seat occupied
recognition
J706
Power module
or le t headlight
J667
Power module or
right headlight
J668
Level control
J197
Electric parking
and hand brake
J540
Headlight range
control
J431
Automatic
transmission
J217
Airbag
J234
ABS with EDL
J104
Engine electronics 1
J623
Diagnosis connection
T16
Control unit in dash
panel insert
J285
Distance control
J428
Data bus diagnosis
or data bus
J533
Door control unit,
driver’s side
J386
Door control unit,
passenger’s side
J387
Door control unit,
rear le t
J388
Door control unit,
rear right
J389
Seat adjustment
with memory
Steering column
adjustment
J136
Seat adjustment
with memory,
passenger’s side
J521
Trailer detection
J345
Steering column
electronics
J527
Multi- unction
steering wheel
J453
Steering-angle
sensor
G85
Power management
J644
Auxiliary heating
J364
Parking aid
J446
On-board power
supply 2
J520
Access and
start authorisation
J518
On-board power
supply
J519
Centr. contr. unit or
convenience system
J393
Climatronic
J255
Tyre pressure
monitoring
J502

7
326_027
Display and
operating unit or
ront in ormation
J523
Tel e ph one
transmitter and
or telephone
R36
CD changer
R41
Digital
sound package
J525
Switch or
access and
start authorisation
E415
Antenna read-in
unit or keyless access
authorisation
J723
Wiper motor
J400
Sensor or rain and
light detection
G397
Passenger
compartment
monitoring
G273
Alarm horn
H12
Fresh air an
J126
Re rigerant pressure and
re rigerant temperature
G395
Tra nsmitt er,
ront le t
G431
Transmi t ter,
ront right
G432
Transmitter,
rear le t
G433
Transmitter,
rear right
G434
Antenna, rear
R96
Tel e p ho n e /
telematics
J526
Handset
or telephone
R37
Navigation
with CD drive
J401
TV tuner
R78
Radio module
R
Voice input
J507
MOST bus
CAN Instrument cluster
CAN Diagnosis
CAN Drive
CAN Convenience
CAN Distance control
LIN bus
Various sub-bus systems
Wireless transmission
– Bluetooth signal

8
Overview
Installation positions of fuses and relays
1 E box in radiator tank, le t
2 Relay and use holder behind
dash panel, le t
3 Fuse holder in dash panel, le t
4 Main use carrier in radiator tank, right
5 Fuse holder in dash panel, right
6 Relay and use holder in the boot, right

9
326_148

10
The basic design o the control unit or power
management is the same as the control unit used in
the Audi A8 ‘03.
It is installed in the boot well, next to the battery.
This control unit has been adapted or use in the
Audi A6 ’05 in that it now has revised so tware,
which shows the battery condition rather than the
battery charge level in the MMI display.
Furthermore, the diagnosis tester can be used to
read out history data, i.e. data relating to the
condition o the on-board power supply in the past.
Convenience electrics
Re erence
The basic unctions o the control unit or power
management J644 are described in the SSP 287.
Battery condition
The battery condition indicates how e icient the
battery is. The e iciency is determined rom the
battery charge level and the ability to start.
Advantages o the battery condition:
– The cut-o stages can be allocated directly to the
battery condition.
– The messages in the central display o dash
panel insert J285 always appear or the same
battery condition reading.
– A 100 % display indicates that no cut-o stage
will be set the next time the engine is switched
o .
326_072
User Car On-board manual
Battery condition
Systems Maintenance
Control unit for power management J644
326_094

Audi
Audi A6 2005>
2005 (5)
Saloon
BBJ 3.0l Motronic / 160 kW
Guided ault- inding
Function/component selection
Selecting a function or component
Electrical system (Rep. Gr. 01; 90 - 97)
01 – Sel -diagnosis systems
61 – Battery control
J644 – Control unit or power management, Functions
A – Battery, Charge level
A – Battery, Battery testing
J644 – Power management, General description
J644 – Control unit or power management, Coding
J644 – Read out history data
J644 – Power management, Read measured-value blocks
J644 – Power management, Query ault memory
J644 – Data link tests or generator voltage
J644 – Replace control unit
J644 – Power management, Activate/deactivate Transport mode
Battery change history
Data or the last three battery changes is stored.
Power balance history – driving (= engine on)
The power balance and duration o the last ive
journeys are logged.
Power balance history – idle (= engine off)
The power balance and duration o the last ive idle
times are logged.
Other data is not relevant or Customer Service.
History data
The diagnosis tester can be used to read out
data rom the control unit or power management,
which makes it much easier to analyse the on-board
power supply and the battery.
Open circuit voltage history
I the battery open-circuit voltage is less than the
threshold values o 12.5 volts, 12.2 volts and
11.5 volts, an entry is written to the history data.
The last our entries can always be read out.
Voltage measurement starts when
– CAN Convenience is in Sleep mode and
– terminal 15 is switched o or at least 2 hours
and
– the vehicle’s power consumption is < 100 mA.
Voltage measurement ends when
– the voltage increases or
– the current increases or
– the control unit triggers Sleep mode or
– the control unit detects a new battery.
Closed circuit current history
I the closed-circuit current exceeds the threshold
value o 50 mA, an entry is written to the history
data. The last ten entries can be read out.
Current measurement starts when
– CAN Convenience is in Sleep mode and
– terminal 15 is switched o or at least 2 hours
and
– the vehicle’s power consumption is > 50 mA.
Current measurement ends when
– the current decreases or
– the control unit triggers Sleep mode.
Breakdown analysis
I the control unit or power management detects
the status "Cannot start vehicle", an entry is written
to the history data.
Cut off level history
Data or the last 15 cut-o levels is stored.
Steady battery discharge
The battery condition is 100 % when the battery is
charged.
As soon as cut-o level 1 is activated, the MMI
"Battery condition" display drops to 90 % and then
goes down to 60 % in steps. I cut-o level 1, 2 or 5
is set when the display reads 90 %, the message
"Power-saving mode active" appears or a short time
on the central display o dash panel insert J285.
In addition, the battery symbol in the dash panel
insert indicates power-saving mode or the entire
load switch-o duration.
As soon as cut-o level 3 is activated, the "Battery
condition" display drops to 50 % and then goes
down to 20 % in steps.
I the battery condition drops to 10 %, cut-o level 6
is active. In cut-o level 6, the message
"BATTERY LOW" appears in the central display o the
dash panel insert a ter the ignition is switched on.
326_061
326_061
326_036
POWER SAVING
MODE
ACTIVE
BATTERY
LOW
Battery condition
Cut-o levels 1, 2 or 5
Cut-o level 3
POWER SAVING
MODE
ACTIVE
BATTERY
LOW
Time/Minutes
Cut-o level 6
Time/Minutes
POWER SAVING
MODE
ACTIVE
12
326_123

Convenience electrics
Function diagram
Legend
E369 Central locking button or outer door handle,
driver’s side*
E370 Central locking button or outer door handle,
passenger’s side*
E371 Central locking button or outer door handle,
rear le t*
E372 Central locking button or outer door handle,
rear right*
E408 Button or access and start authorisation
E415 Switch or access and start authorisation
F272 Outer door handle switch, driver’s door*
F273 Outer door handle switch, passenger’s door*
F274 Outer door handle switch, rear le t*
F275 Outer door handle switch, rear right*
F305 Switch or gearbox position P**
G415 Sensor or outer door handle contact,
driver’s side*
G416 Sensor or outer door handle contact,
passenger’s side*
G417 Sensor or outer door handle contact,
rear le t*
G418 Sensor or outer door handle contact,
rear right*
J53 Starter relay
J329 Voltage supply relay, terminal 15
J386 Door control unit, driver's side
J387 Door control unit, passenger's side
J388 Door control unit, rear le t
J389 Door control unit, rear right
J518 Control unit or access and
start authorisation
J623 Engine control unit
J694 Voltage supply relay, terminal 75x
J695 Starter relay 2
J723 Antenna read-in unit or keyless access
authorisation*
R47 Antenna or central locking and
anti-the t warning system
R134 Antenna on driver’s side or access
access and start authorisation*
R135 Antenna on passenger’s side or access
access and start authorisation*
R137 Luggage compartment antenna or access
access and start authorisation*
R138 Passenger compartment antenna 1 or
access and start authorisation*
* only or vehicles with Advanced Key
** only or vehicles with automatic transmission
1 Terminal 50 (to starter B)
2 CAN Convenience High
3 CAN Convenience Low
4 P/N signal rom control unit or
automatic transmission J217**
5 Terminal 58s (lighting)*
6 Signal rom brake light switch F*
Positive supply
Input signal
Output signal
Ground
Bi-directional line
13
Access and start authorisation
Start request
Ulock

15
326_038

16
The Advanced Key system was introduced with the
Audi A8 '03 and has been undamentally revised or
the Audi A6 ’05.
The most important new eature is that the control
unit or access and start authorisation has been
combined with the actuator or steering column
locking.
Convenience electrics
System overview

17
326_147
1 Door control unit, driver's side J386
2 Control unit or on-board power supply J519
3 Control unit or access and start
authorisation J518
4 Switch or access and start authorisation E415
5 Central locking button or outer door handle,
driver's side E369
Outer door handle switch in driver’s door F272
Sensor or outer door handle contact,
driver’s side G415
6 Antenna read-in unit or keyless access
authorisation J723
7 Antenna on driver’s side or access
and start authorisation R134
8 Door control unit, rear le t J388
9 Passenger compartment antenna 1 or
and start authorisation R138
10 Door control unit, passenger's side J387
11 Central locking button or outer door handle,
rear le t E371
Outer door handle switch, rear le t F274
Sensor or outer door handle contact,
rear le t G417
12 Central locking button or outer door handle,
passenger’s side E370
Outer door handle switch in passenger’s
door F273
Sensor or outer door handle contact,
passenger's side G416
13 Antenna on passenger’s side or access
and start authorisation R135
14 Door control unit, rear right J389
15 Antenna or central locking and
anti-the t warning system R47
16 Central locking button or outer door handle,
rear right E372
Outer door handle switch, rear right F275
Sensor or outer door handle contact, rear
right G418
17 Boot antenna or access
and start authorisation R137

18
Division o unctions
System control is broken down into three basic
modules:
– the control unit or access and
start authorisation J518,
– the antenna read-in unit or keyless access
authorisation J723 and
– the switch or access and
start authorisation E415.
All three components communicate with each other
over a local single-wire bus.
The control unit or access and start authorisation is
the master o the system and a participant on
Convenience. The same control unit is installed or
all system versions.
The antenna read-in unit or keyless access
authorisation is only installed with the
Advanced Key option. It serves as the inter ace
between the antennae, sensors and the control unit
or access and start authorisation.
The switch or access and start authorisation is
installed in various versions, depending on the
transmission, radio requency o the central locking
system and the Advanced Key option. An evaluation
electronic device is also integrated into the switch.
Convenience electrics
326_064
Access and
start authorisation
J518
Antenna read-in
unit or
keyless access
authorisation
J723
Switch or
access and start
authorisation
E415

19
Versions
The switch or access and start authorisation is
available in the ollowing versions:
– with and without Advanced Key unction
– with and without ignition key anti-removal lock
– or radio requencies o 315 MHz, 433 MHz or
868 MHz
Functions
The switch or access and start authorisation
includes other unctions apart rom the ignition
switch unction:
– Evaluation o the key position o the ignition
switch:
The ignition switch evaluates the ignition key
position using our switches.
The switch in ormation is trans erred to the
control unit or access and start authorisation in
binary code via the local bus and also or
monitoring purposes, via two lines.
The lock barrel in the ignition switch is not coded
mechanically, which means that the turning
movement can be per ormed with every
A6 '05 key.
– Sa ety branch or the steering lock o the control
unit or access and start
authorisation:
In addition to the switch-o s in the control unit
or access and start authorisation, the voltage
supply or the motor o the electromechanical
steering lock is interrupted in the switch or
access and start authorisation in order to
prevent the steering column locking
automatically.
I terminal 15 is switched on, the voltage supply
is always switched o .
326_066
326_067
Switch or access and start authorisation E415
ULock
326_122
Emergency release

20
– Reading in position P o the automatic
transmission rom the switch or gearbox
position P F305:
The signal is used to activate the integrated,
magnetic ignition key anti-removal lock. I the
vehicle battery is lat, the key can be removed by
pressing the mechanical emergency release.
– Reading in the in ormation rom the button or
access and start authorisation E408 (only or
vehicles with Advanced Key):
For sa ety reasons, the positions o the button or
access and start authorisation are evaluated by
the switch or access and start authorisation.
–
– Reading in the in ormation rom the antenna or
central locking and anti-the t warning
system R47:
The switch or access and start authorisation
passes the data, which the vehicle key sends via
remote control, on to the control unit or access
and start authorisation. The control unit
evaluates the data.
– Reading in the signal rom the brake light
switch F (only or vehicles with Advanced Key):
To start the vehicle using the button or access
and start authorisation, the brake pedal must be
actuated.
– Exchanging data with the key using the
integrated read coil:
I a key is inserted into the switch or access and
start authorisation (= S contact on), the
electronics system transmits electric power into
the key via the read coil. The key then sends the
key identi ication into the switch via the
transponder and the read coil. This sends the
in ormation to the control unit or access and
start authorisation.
Convenience electrics
326_069
326_068
326_065

21
The electromechanical steering column lock was
integrated into the control unit or access and start
authorisation.
Functions
– Terminal control:
The control unit or access and start
authorisation puts the in ormation about
terminal 15, 75x, 50, S and P on
CAN Convenience.
The control unit also activates the relays or
terminal 15 and 75x and passes the start request
signal on to the engine control unit.
– Locking the steering column:
The motor and gears or locking the steering
column are integrated into the control unit or
access and start authorisation.
The position o the lock is checked using two
integrated micro switches. Terminal 15 is only
switched on a ter the steering is unlocked ully.
– Immobiliser and component protection:
The control unit is the master or these
unctions.
Control unit or access and start authorisation J518
326_095

22
– CAN Communication:
The control unit is a participant on
CAN Convenience. Data exchange between all
the components o the access and start
authorisation system is per ormed via the
control unit.
It is also the diagnosis inter ace or the
components involved. All data, e.g. code,
immobiliser data, etc. is stored in the control unit
or access and start authorisation.
– Reading in the P/N signal rom the control unit
or automatic transmission J217:
The signal is used to activate the displays
relating to engine start in dash panel insert J285.
Convenience electrics
326_062 326_063
SELECT
N OR P
TO START
THE ENGINE
SELECT
N OR P
START THE
ENGINE