Audi TT (2007 year). Manual — part 3

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
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.

3

Safety precautions

When working on the fuel system note the following warnings:

WARNING

Risk of injury - fuel system operates under pressure.

♦ Wrap a clean cloth around the connection before opening

the fuel system. Then release pressure by carefully loos‐

ening the connection.

♦ Wear protective gloves.
♦ Wear safety goggles.

The fuel can become extremely hot. This can cause injuries.

♦ In extreme cases the temperature of the fuel lines and the

fuel can be up to 100 °C after the engine is switched off.

Allow the fuel to cool down before disconnecting the lines

- danger of scalding.

♦ Wear protective gloves.
♦ Wear safety goggles.

Observe the following points to prevent personal injuries and

damage to the injection and glow plug system:
♦ Always switch off the ignition before connecting or discon‐

necting tester cables or electrical wiring for the injection or

glow plug system.

♦ Always switch off ignition before washing engine.
♦ Faults are stored in engine control unit if electrical connectors

have been unplugged:

– “Interrogate fault memory” in “Vehicle self-diagnosis”.

Caution

To prevent damage to the electronic components when dis‐

connecting the battery:

♦ Observe notes on procedure for disconnecting the battery.
♦ Always switch off the ignition before disconnecting the

battery.

3. Safety precautions

3

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
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.

When working on the cooling system note the following warnings:

WARNING

Hot steam/hot coolant can escape - risk of scalding.

♦ The cooling system is under pressure when the engine is

hot.

♦ To allow pressure to dissipate, cover filler cap coolant on

expansion tank with cloth and open carefully.

Risk of injury as the radiator fans may start up automatically.

♦ Unplug electrical connectors before starting to work in the

area of radiator cowl.

Caution

Overheating can occur if the filler cap is not fitted properly.

♦ Firmly close filler cap on coolant expansion tank.

Note the following if testers and measuring instruments have to

be used during a road test:

WARNING

Accidents can be caused if the driver is distracted by test

equipment while road-testing, or if test equipment is not prop‐

erly secured.
Persons sitting in the front passenger's seat could be injured if

the airbag is triggered in an accident.

• The use of test equipment while driving causes distraction.
• There is an increased risk of injury if test equipment is not

secured.

TT Coupé:
Test equipment must always be secured on the rear seat with

a strap and operated from the rear seat by a second person.
TT Roadster:

♦ Move the passenger's seat back as far as it will go.
♦ Use only vehicle diagnosis and service information sys‐

tem -VAS 5052- or diagnosis system -VAS 5053- .

♦ The test equipment -1- must rest flat on the passenger's

thighs (as shown in illustration) and must be operated by

the passenger.

4

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
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.

4

General repair instructions

4.1

Rules for cleanliness when working on

fuel supply system, injection system and

turbocharger

Even small amounts of dirt can cause malfunctions. For this rea‐

son, please observe the following rules when working on the fuel

supply system, injection system and turbocharger:
♦ Carefully clean connection points and the surrounding area

with engine cleaner or brake cleaner and dry thoroughly before

opening.

♦ Seal off open pipes/lines and connections using engine bung

set -VAS 6122- .

♦ Place parts that have been removed on a clean surface and

cover them over. Do not use fluffy cloths.

♦ Carefully cover or seal open components if repairs cannot be

carried out immediately.

♦ Only install clean components; replacement parts should only

be unpacked immediately prior to installation. Do not use parts

that have not been stored in the proper packaging (e.g. in tool

boxes etc.).

♦ When the system is open: Do not work with compressed air.

Do not move the vehicle unless absolutely necessary.

♦ Protect unplugged electrical connectors against dirt and mois‐

ture and make sure connections are dry when attaching.

4.2

Checking for leaks in the fuel system

Procedure
– Allow engine to run for several minutes at moderate rpm.
– Switch off ignition.
– Check complete fuel system for leaks.
– If leaks are found although the connections have been tight‐

ened to the correct torque, the relevant component must be

renewed.

– Road-test vehicle and accelerate with full throttle at least once.
– Then inspect high-pressure section of fuel system again for

leaks.

4.3

Contact corrosion!

Contact corrosion can occur if unsuitable fasteners are used (e.g.

bolts, nuts, washers, etc.).
For this reason, only fasteners with a special surface coating are

used.
Additionally, all rubber and plastic parts and all adhesives are

made of non-conductive materials.
Always install new parts if you are not sure whether used parts

can be re-fitted ⇒ Electronic parts catalogue .
Note the following:
♦ We recommend using only genuine replacement parts; these

have been tested and are compatible with aluminium.

4. General repair instructions

5

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
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.

♦ We recommend the use of Audi accessories.
♦ Damage caused by contact corrosion is not covered under

warranty.

4.4

Checking vacuum system

Special tools and workshop equipment required
♦ Hand vacuum pump -VAS 6213-

Procedure
– Check all vacuum lines in the complete vacuum system for:
♦ Cracks
♦ Traces of animal bites
♦ Kinked or crushed lines
♦ Lines porous or leaking
– Check vacuum line to solenoid valve and from solenoid valve

to corresponding component.

– If a fault is stored in the fault memory, check the vacuum lines

leading to the corresponding component and also check the

remaining vacuum lines in the system.

– If it is not possible to build up pressure with the hand vacuum

pump -VAS 6213- or if the pressure drops again immediately,

check the hand vacuum pump and connecting hoses for leaks.

4.5

Routing and attachment of pipes, hoses

and wiring

Mark hydraulic lines, vacuum lines and electrical wiring before

removal so they can be re-installed in the original positions and

correctly connected. Make sketches or take photographs if nec‐

essary.

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