VOLKSWAGEN Touareg User Manual

Service.

Self-Study Programme 298

The Touareg
Electrical System

Design and Function

Vehic l es w i t h off-road capability are no longer
just utility vehicles for a limited group of people.

The off-road vehicle features a number of hi-tech
convenience systems for improved comfort.

At all levels in the population they are now
becoming more and more sought after.

This Self-Study Programme is designed to help
you learn about the electrical and electronic
systems in the Volkswagen Touareg.

This Self-Study Programme explains the design

and function of new developments.

The contents will not be updated.

2

S298_052

NEW Important

Note

Please refer to the relevant Service Literature

for current inspection, adjustment and repair

instructions.

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Onboard power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Battery concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Onboard power supply management. . . . . . . . . . . . . . . . 30

Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Networked functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Test your sel f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3

Introduction

Fuse boxes and relay slots in vehicle's electrical system

Fitting locations

The fuse boxes and relay slots can be found at
various locations in the vehicle due to the fact
that the onboard power supply does not have
a central layout.

The illustrations here provide an overview of their
fitting locations.

E-box
on left under dash panel

Fuse box
on right under dash panel

More detailed information can be
found in the electronic service
information system (ELSA).

E-box
on left in plenum chamber

4

Starter battery
under luggage compartment

Back-up fuse box
under driver's seat

S298_001

Fuse box
on left of dash panel

Onboard power
supply battery
under driver's seat

5

Introduction

The data bus network

Networking

In order that the control units can exchange
information between each other, they are
connected in a network via the Gateway in the
dash panel insert J285.

The data exchange allows the control units to
access various kinds of information in the vehicle.
The more information a control unit has about
the current driving situation, the greater the level
of safety and comfort.

To en sure the exchange of data can take place,
the control units are connected together in
a network via a CAN bus system. Due to reasons
of safety and because the data bus systems work
at different rates of transfer, the control units are
allocated to different CAN bus systems. If one
data bus system should fail, the others can
continue to function.

The CAN bus systems are separated as follows

* Turbocharger
control unit

*Reserved

J285 Dash panel insert
(Gateway)

J401
Navigation control
unit

J526
Telephon e c ontrol unit

R12
8-channel amplifier

J623
Engine control unit

J234
Airbag control unit

-Drive Train CAN bus,

-Convenience CAN bus,

-Infotainment CAN bus.

Gateway

Drive Train CAN
bus

Convenience
CAN bus

Infotainment
CAN bus

R78
TV tuner

J499
Te le m a ti c s control unit
(USA only)

J162
Additional water
heater control unit

J400
Wiper motor control
unit

CAN bus

Communications
line

Virtual
Communications
line

S298_027

6

J217
Autom. gearbox
control unit

J104
ABS with E DL
control unit

J646
Tra ns fer box control
unit

J647
Tra nsve rse l o ck- u p
control unit

J527
Steering column
electronics control
unit

J255
Climatronic control
unit

J446
Parking aid control
unit

J393
Convenience
system central
control unit

J518
Entry and start
authorisation
control unit

E265
Rear operating and
display unit for
Climatronic

J345
Tra il er detection
control unit

J386
Driver door control
unit

J197
Adaptive
suspension control
unit

J519
Onboard power
supply control unit

J502
Tyre p ressure
monitor
control unit

J387
Front passenger
door control unit

* Off-road
stabilisation
control unit

*Reserved

J136
Seat adjustment
control unit
Driver memory

J521 Seat
adjustment control
unit Front
passenger memory

J388
Rear left door
control unit

J343
Left gas discharge
lamp control unit

J389
Rear right door
control unit

J344
Right gas discharge
lamp control unit

S298_003

7

Introduction

The control units in the Drive Train CAN bus

Control units

The illustrations here provide an overview of the
fitting locations.

The Drive Train CAN bus operates at a data
transfer rate of 500 kbit/s. The data is
transmitted via the CAN High and CAN Low line.
Both wires are entwined together. The cable
colour for CAN High is orange/black and for
CAN Low it is orange/brown.

Steering column electronics control unit J527
on steering column

Autom. gearbox control unit J217
Tra nsfer box control unit J646
under front passenger's seat

Engine control unit J623
in right of plenum chamber

ABS with EDL control unit J104
in right of plenum chamber

8

Airbag control unit J234
under centre console cover

Adaptive suspension
control unit J197
on right in luggage
compartment

Tran sverse lock-up control unit J647
on left at rear in wheel housing

S298_002

Windscreen heater control unit J505
under driver's seat
Control unit is not connected to CAN bus

Entry and start authorisation control unit J518
on left under dash panel

9

Introduction

The Drive Train CAN bus control units

Control units

The illustrations here provide an overview of the
fitting locations.

The Convenience CAN bus operates at a data
transfer rate of 100 kbit/s.
The data is transmitted via the CAN High and
CAN Low line. Both wires are entwined together.
The cable colour for CAN High is orange/green
and for CAN Low it is orange/brown. The CAN
bus is single wire compatible, which means that if
one CAN bus wire should fail, the CAN
messages can be transmitted via the other wire.

Steering column
electronics control unit J527
on steering column

Climatronic control unit J255
in left of dash panel

Entry andstart authorisation
control unit J518
Onboard power supply
control unit J519
on left under dash panel

10

Convenience system central control unit J393
Trai le r detection control unit J345
on right in luggage compartment

Parking aid control unit J446
on left at rear in wheel housing

S298_044

Tyre pressure monitor control unit J502
on left A-pillar

Rear left door control unit J388
Rear right door control unit J389
behind door trim

Driver door control unit J386
Front passenger door control unit J387
behind door trim on left and right

11

Introduction

The Infotainment CAN bus control units

Control units

The illustrations here show the fitting locations of
the control units for the Infotainment CAN bus.

The Infotainment CAN bus operates at a data
transfer rate of 100 kbit/s.
The data is transmitted via the CAN High and
CAN Low line. Both wires are entwined together.
The cable colour for CAN High is orange/violet
and for CAN Low it is orange/brown.
The Infotainment CAN bus is single-wire
compatible, which means that if one wire fails,
data can be sent and received via the other wire.

Tel e ph o n e c on t rol unit J526
under front passenger's seat

12

Wiper motor control unit J400
in plenum chamber

Amplifier R12
CD player R41
(not connected to CAN bus)
TV tuner R78
on right in luggage compartment

Radio R
Navigation control unit J401
in centre of dash panel

S298_045

Additional water heater J162
on left in wheel arch

13

Onboard power supply

The fuse and electrical boxes

The fuse boxes can be found in the dash panel
on the left and right-hand side.
The back-up fuse box is under the driver's seat
and the E-boxes can be found on the left in the
plenum chamber and under the dash panel.

Fuse box on left of dash panel

The fuse box on the left of the dash panel, for
example, houses the fuses for the following
control units:

-Onboard power supply control unit

-Entry and start authorisation control unit

-Tyre pressure monitor control unit

-Engine control unit

-Airbag control unit

-ABS with EDL control unit

-Steering column electronics control unit

-Convenience system central control unit

-and fuses for other electrical consumers

Fuse box on left of dash panel

S298_004

14

Fuse box on right of dash panel

Fuse box on right of dash panel

The fuse box on the right of the dash panel
houses the following fuses:

-Trailer detection control unit

-Parking aid control unit

-Telephone control unit

-ABS with EDL control unit

-Navigation control unit

-CD changer

-TV tuner

-Radio

-Radio amplifier

-Convenience system central control unit

-Adaptive suspension control unit

-Automatic gearbox control unit

-Convenience system central control unit

-Telephone

-and fuses for other electrical consumers

S298_005

The exact fuse allocation can be found
in the electronic service information
system (ELSA).

15

Onboard power supply

Back-up fuse box under driver's seat

The following fuses and relays can be found in
the back-up fuse box:

Fuses:

-Fuse sockets

-Fuse for terminal 15 relay

-Battery parallel circuit relay

-E-socket

-Fuse for onboard power supply control unit

-Starter lead diagnosis

-Fuse for adaptive suspension, compressor

Relays:

-Battery master / isolation relay E74

-Relay for terminal 15

-Charging circuit relay for vehicles with dual
battery electrical system

Back-up fuse box under driver's seat

Battery master /
isolation switch

Charging circuit relay for
additional battery

Relay for terminal 15

S298_006

E-box under dash panel

The following relays can be found in the E-box:

- Servotronic relay D1

-Relay for tailgate closing aid D2

-Relay for adaptive suspension compressor D3

-Relay for power supply terminal 15 D5

-Relay for additional water heater D6

-Relay for heated rear windscreen D7

-Relay for seat heating D8

-Additional relay for brake lights D9

-Relay for spare wheel E2

-Relay for manual air-conditioning system E3

-Relay for circulation pump E4

-Relay for start-up consumers E5

-Relay for headlight washer system E7

-Relay for residual warmth E8

E-box under dash panel

E2

E3

E4

E7E5E8

D3

D2

D1

D6

D9

D5

D8

D7

S298_007

16

E-box on left of plenum chamber

The allocation of the fuses and relays is
dependent on the engine type. This layout is
specific to the AZZ engine and is shown here for
demonstration purposes only.

Fuses:

-Fan

-Secondary air pump

-Injectors

-Engine control unit, variable camshaft timing,
intake manifold changeover valve, thermal
heating

-Leak diagnosis of fuel tank,
high pressure sender for air conditioning,
radiator fan control unit

E-box in plenum chamber

A2 A4

Relays:

-Terminal 30 power supply A1 / A3

-Secondary air pump A4

-Additional coolant pump A5

-Fuel pumps A6 / C19

-Terminal 50 power supply C20

A6

A5

A1 A3

C20

C19

B2 B4

B1 B3

B6

B5

S298_008

Fuse boxes will vary depending on the vehicle and engine type.
For precise details on the fuse boxes, please refer to the electronic service information system
(ELSA).

17

Onboard power supply

Battery master / isolation rely E74

Battery isolation

In a crash, the battery is isolated from the starter
lead via the battery master switch. This prevents
a short circuit in the starter lead which could lead
to a fire.

The isolation signal is received by the battery
master switch from the airbag control unit J234
via a separate signal wire.

Recognition of isolation

If the battery has been isolated, a white cover
will be seen in the sight-glass instead of a copper
winding. The relay should then be reset using the
reset switch, otherwise starting the engine will not
be possible.

Battery master / isolation switch

Reset switch

Sight-glass

S298_017

If the onboard power supply has a twin battery
concept, the onboard power supply control unit
checks the position of the battery master switch.
If the master switch is on, starting the vehicle
using the starter battery will be prevented.

Key

ABattery
BStarter motor
CAlternator
E74 Battery master / isolation switch
J234 Airbag control unit
J285 Dash panel insert
TV cable distributor
V Onboard consumers

Before resetting, the starter lead must be checked for short circuits. For this reason, resetting
should only be carried out by a specialist workshop.

Electrical circuit

TV

B

J285

J234

V

TV

E74

C

A

S298_040

18