Audi TT 4 User Manual
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.
Service
Workshop Manual
Audi TT 1999 ➤
Fuel supply system, petrol engines
Engine ID
Edition 06.2007
AJQ APP APX ARY AUM AUQ BAM BHE ATC
AWP AMU BEA BFV BPF BVP BVR
Service Department. Technical Information
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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.
Service
List of Workshop Manual Repair GroupsList of Workshop Manual
Repair GroupsList of Workshop Manual Repair Groups
Re pa ir G ro up
20 - Fuel supply system
Technical information should always be available to the foremen and mechanics, because their
careful and constant adherence to the instructions is essential to ensure vehicle road-worthiness and
safety. In addition, the normal basic safety precautions for working on motor vehicles must, as a
matter of course, be observed.
All rights reserved.
No reproduction without prior agreement from publisher.
Copyright © 2010 Audi AG, Ingolstadt A0057006220
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
Contents
20 - Fuel supply system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1 General repair instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Rules for cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Test conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Contact corrosion! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Tank flap - all versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Tank flap - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Removing and installing tank flap unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Fuel tank - rest-of-world vehicles (front-wheel drive) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Fuel tank with attached components - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2 Draining fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Removing and installing fuel tank with attached components . . . . . . . . . . . . . . . . . . . . . . 10
4 Fuel tank - USA vehicles (front-wheel drive) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1 Fuel tank with attached components and fuel filler neck - exploded view . . . . . . . . . . . . . . 15
4.2 Draining fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3 Removing and installing fuel tank with attached components . . . . . . . . . . . . . . . . . . . . . . 21
5 Fuel delivery unit and fuel gauge sender - all vehicles with front-wheel drive . . . . . . . . . . 26
5.1 Fuel delivery unit and fuel gauge sender - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 Fuel system pressurisation pump G6 - electrical test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.3 Checking fuel pump delivery rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.4 Removing and installing fuel delivery unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5 Checking fuel gauge sender G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.6 Removing and installing fuel gauge sender G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6 Fuel tank - rest-of-world vehicles (four-wheel drive) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.1 Fuel tank with attached components - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.2 Draining fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.3 Removing and installing fuel tank with attached components . . . . . . . . . . . . . . . . . . . . . . 43
7 Fuel tank - USA vehicles (four-wheel drive) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
7.1 Fuel tank with attached components and fuel filler neck - exploded view . . . . . . . . . . . . . . 47
7.2 Draining fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
7.3 Removing and installing fuel tank with attached components . . . . . . . . . . . . . . . . . . . . . . 53
8 Fuel delivery unit and fuel gauge sender - all vehicles with four-wheel drive . . . . . . . . . . . . 58
8.1 Fuel delivery unit and fuel gauge sender - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . 58
8.2 Fuel system pressurisation pump G6 - electrical test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
8.3 Checking fuel pump delivery rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
8.4 Removing and installing fuel delivery unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
8.5 Checking fuel gauge sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
8.6 Removing and installing fuel gauge sender G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
8.7 Removing and installing fuel gauge sender 2 G169 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
8.8 Suction-jet pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
8.9 Removing and installing suction-jet pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9 Activated charcoal filter system - rest-of-world vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.1 Activated charcoal filter system - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
10 Activated charcoal filter system and tank leak diagnostic system - USA vehicles . . . . . . . . 75
10.1 Activated charcoal filter system and tank leak diagnostic system - exploded view . . . . . . 75
10.2 Checking activated charcoal filter solenoid valve 2 N115 . . . . . . . . . . . . . . . . . . . . . . . . . . 76
10.3 Removing and installing activated charcoal filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
10.4 Activated charcoal filter solenoid valve 1 N80 and vacuum reservoir - exploded view . . . . 83
10.5 Routing of pipes/hoses for activated charcoal filter system and tank leak diagnostic
system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Contents i
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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
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Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
10.6 Tank leak diagnostic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
10.7 Automatic tank leak diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
10.8 Performing tank leak diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
10.9 Checking fuel tank system and tank breather system for leaks . . . . . . . . . . . . . . . . . . . . . . 89
10.10 Fuel system diagnostic pump V144 - exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
10.11 Checking fuel system diagnostic pump V144 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
10.12 Removing and installing fuel system diagnostic pump V144 . . . . . . . . . . . . . . . . . . . . . . 97
11 Accelerator mechanism - all vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.1 Accelerator pedal with accelerator pedal module - exploded view . . . . . . . . . . . . . . . . . . . . 98
11.2 Removing and installing accelerator pedal module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
11.3 Adapting kick-down function - vehicles with automatic gearbox or dual clutch gearbox . . 99
11.4 Accelerator mechanism on right-hand drive vehicles without accelerator pedal module -
exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
11.5 Adjusting accelerator position sender G79 - right-hand drive vehicles without accelerator
pedal module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
ii Contents
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Fuel supply system, petrol engines - Edition 06.2007
20 – Fuel supply system
1 General repair instructions
1.1 Safety precautions
When working on the fuel system note the following warnings:
WARNING
Risk of injury - fuel system operates under high pressure.
♦ To reduce the pressure in the fuel system, wrap a clean
cloth around the connection and carefully loosen the con‐
nection.
Perform the following steps before starting to work on the fuel
supply system:
Audi TT 1999 ➤
WARNING
Mobile phones can cause an explosion risk.
♦ Ensure that any mobile phones are well clear of the work‐
bay.
Caution
Electronic components are susceptible to damage.
♦ Observe notes on procedure for disconnecting the battery.
♦ Disconnect battery ⇒ Rep. Gr. 27 .
♦ Briefly open filler cap for fuel tank and close again.
When removing and installing components from a full or partly full
fuel tank, note the following:
Fuel tank must not be full. The amount of fuel which can be left in
the tank is indicated in the corresponding procedure description.
Drain the tank if necessary. Procedure:
♦ Rest-of-world vehicles (front-wheel drive) ⇒ page 8 .
♦ Rest-of-world vehicles (four-wheel drive) ⇒ page 40 .
♦ USA vehicles (front-wheel drive) ⇒ page 19 .
♦ USA vehicles (four-wheel drive) ⇒ page 51 .
Before commencing work, switch on exhaust extraction system
and place an extraction hose close to the sender opening in the
fuel tank to extract escaping petrol fumes. If no exhaust extraction
system is available, a radial fan with a displacement of at least
15 m3/h can be used (the fan motor must be clear of the air
stream).
Avoid skin contact with fuel. Wear fuel-resistant gloves.
1. General repair instructions 1
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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
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Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
When removing and installing the fuel tank, note the following:
Fuel tank must be empty to reduce weight. Drain the tank if nec‐
essary. Procedure:
♦ Rest-of-world vehicles (front-wheel drive) ⇒ page 8 .
♦ Rest-of-world vehicles (four-wheel drive) ⇒ page 40 .
♦ USA vehicles (front-wheel drive) ⇒ page 19 .
♦ USA vehicles (four-wheel drive) ⇒ page 51 .
1.2 Rules for cleanliness
Even small amounts of dirt can cause malfunctions. When work‐
ing on the fuel supply system and injection system, pay careful
attention to the following basic rules:
♦ Carefully clean connection points and the surrounding area
with engine cleaner or brake cleaner and dry thoroughly before
opening.
♦ Seal off open lines and connections with clean plugs or sealing
caps immediately.
♦ Place parts that have been removed on a clean surface and
cover them over. Use only lint-free 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 been previously unpacked and stored away loose
(e.g. in toolboxes, 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.
1.3 Test conditions
• Battery voltage at least 12.5 V
• Fuse for fuel system pressurisation pump -G6- OK ⇒ Current
flow diagrams, Electrical fault finding and Fitting locations.
• Fuel pump relay -J17- OK ⇒ Current flow diagrams, Electrical
fault finding and Fitting locations.
•
Fuel tank at least 1/4 full.
• Fuel filter OK
• Fuel lines OK (not obstructed or crushed).
• Ignition off.
1.4 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 .
2 Rep. Gr.20 - Fuel supply system
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with respect to the correctness of information in this document. Copyright by AUDI AG.
Fuel supply system, petrol engines - Edition 06.2007
Note the following:
♦ We recommend using only genuine replacement parts; these
have been tested and are compatible with aluminium.
♦ We recommend the use of Audi accessories.
♦ Damage caused by contact corrosion is not covered under
warranty.
Audi TT 1999 ➤
1. General repair instructions 3
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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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
2 Tank flap - all versions
2.1 Tank flap - exploded view
1 - Retaining ring
❑ Small diameter
2 - Retaining ring
❑ Large diameter
3 - Filler cap
❑ With seal
4 - O-ring
❑ Renew if damaged
5 - Tank flap unit
❑ Removing and installing
⇒ page 4
6 - Bolt
❑ To remove tank flap, just
remove the 3 bolts illus‐
trated ⇒ page 4
❑ 4 Nm
7 - O-ring
❑ Renew if damaged
8 - Locking element
9 - Compression spring
10 - Bracket
11 - Bolt
12 - Release cable
13 - Rubber cup
❑ With overflow hose
14 - Filler neck
2.2 Removing and installing tank flap unit
Special tools and workshop equipment required
♦ Front-end hook -3370-
4 Rep. Gr.20 - Fuel supply system
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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.
Fuel supply system, petrol engines - Edition 06.2007
Removing
– Remove the 3 bolts marked by -arrows-.
– Lift tank flap unit out of body vertically using front-end hook
-3370- .
– Remove bolts -arrows- for release cable.
Audi TT 1999 ➤
Installing
• Tightening torque ⇒ page 4 .
Installation is carried out in the reverse order; note the following:
– To avoid kinking overflow hose, install rubber cup as follows:
• Edge of drain hole must be aligned with edge of square hole
-arrows-.
2. Tank flap - all versions 5
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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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
3 Fuel tank - rest-of-world vehicles
(front-wheel drive)
3.1 Fuel tank with attached components - exploded view
1 - Securing strap
❑ Note different lengths
2 - Fuel filter
❑ Note correct position
❑ Installation position: Ar‐
row points in throughflow direction
3 - Fuel supply pipe
❑ Black
❑ To fuel rail
❑ Press release tab on
pipe connector to dis‐
connect
4 - Retaining clamp for fuel fil‐
ter
❑ Installation position
⇒ page 8
5 - Breather pipe
❑ White
❑ From gravity valve to ac‐
tivated charcoal filter
❑ Always remove and in‐
stall together with gravi‐
ty valve ⇒ page 8
6 - Fuel supply pipe
❑ Black
❑ To fuel filter
❑ Connect to connection
“V” on flange.
❑ Press release tab on
pipe connector to dis‐
connect
7 - Fuel return pipe
❑ Blue
❑ From fuel rail
❑ Connect to connection “R” on flange.
❑ Press release tab on pipe connector to disconnect
8 - Electrical connector
❑ For fuel system pressurisation pump -G6- and fuel gauge sender -G-
9 - Bolt
❑ 11 Nm
10 - Cap nut
❑ 10 Nm
6 Rep. Gr.20 - Fuel supply system
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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
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Fuel supply system, petrol engines - Edition 06.2007
11 - Earth connection
❑ To eliminate electrostatic charge
❑ Installation position ⇒ page 7
❑ Ensure that connector is seated firmly on metal ring of fuel filler neck
❑ Secure contact terminal with cap nut -item 10❑ Test procedure after installing ⇒ page 8
12 - Nut
❑ 10 Nm
13 - Bracket
❑ For fuel filler neck
14 - Filler cap
❑ With seal
15 - Retaining ring
❑ Large diameter
16 - Retaining ring
❑ Small diameter
17 - Rubber cup
❑ With overflow hose
❑ Note installation position ⇒ page 5
18 - Fuel tank
❑ Removing and installing ⇒ page 10
19 - Heat shield
❑ For fuel tank
20 - Locking washer
❑ Removing: turn anti-clockwise
❑ 2 Nm
21 - Bolt
❑ 26 Nm
22 - Bolt
❑ 26 Nm
Audi TT 1999 ➤
Installation position of earth connection
– Route earth connection as shown in illustration.
– Ensure that connector -2- for earth connection is properly
seated on metal ring -1- on fuel filler neck.
– Hook earth connection into the two retainers -arrows- on fuel
filler neck.
Note
♦
For illustration purposes, the routing of the earth wire is shown
with the fuel tank removed.
♦
On some versions, only one retainer and a cable tie are fitted.
3. Fuel tank - rest-of-world vehicles (front-wheel drive) 7
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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
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Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
Test procedure for earth connection
– Before securing, make sure that contact terminal -1- of wire
and cap nut -2- are free of corrosion to ensure proper earth
connection to body.
– Check that earth connection is properly secured at front re‐
tainer -arrow- on fuel filler neck.
WARNING
Risk of explosion caused by electrostatic discharge.
♦ After installation, use an ohmmeter to check the electrical
connection between the metal ring on the fuel filler neck
and a bare metal part on the body:
• Specification: approx. 0 Ω
Removing, installing and checking gravity valve
Removing
Note
The gravity valve -1- can only be renewed together with breather
pipe -3-.
– Unclip gravity valve from filler neck and lift it off.
Checking
• Hold gravity valve in a vertical position: it should be possible
to blow through valve.
• Tilt gravity valve by 45°; it should not be possible to blow
through valve.
• Make sure O-ring -2- is not damaged.
Installation position of retaining clamp for fuel filter
– Position retaining clamp as illustrated -arrow-.
Note
The illustration shows the installation position from the front.
3.2 Draining fuel tank
♦
A - Procedure if fuel tank is more than 3/4 full ⇒ page 9 .
♦
B - Procedure if fuel tank is less than 3/4 full ⇒ page 10 .
Special tools and workshop equipment required
8 Rep. Gr.20 - Fuel supply system
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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.
Fuel supply system, petrol engines - Edition 06.2007
♦ Fuel extractor unit -VAS 5190-
Procedure
Observe safety precautions ⇒ page 1 .
Observe rules for cleanliness ⇒ page 2 .
Caution
To prevent damage to the electronic components when dis‐
connecting the battery:
Audi TT 1999 ➤
♦ Observe notes on procedure for disconnecting the battery.
– Disconnect battery ⇒ Rep. Gr. 27 .
– Release the tank flap.
WARNING
Risk of explosion caused by electrostatic discharge.
♦ Secure earth wire of fuel extractor unit -VAS 5190- to a
bare metal part on the body.
A - Procedure if fuel tank is more than 3/4 full
– Detach tapered adapter -2- from shaft end -1- of fuel extractor
unit -VAS 5190- .
– Use insulating tape to mark the extraction hose -arrow- at a
distance of -a- = 1045 mm from the end of the hose.
3. Fuel tank - rest-of-world vehicles (front-wheel drive) 9
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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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
– Remove filler cap from fuel filler neck.
– Screw shaft end of fuel extractor unit -VAS 5190- onto fuel filler
neck.
Note
A ball valve -2- is located at the bottom of the filler neck in the fuel
tank -1-; it must not be damaged by the extraction hose -3-.
– Only push extraction hose into fuel tank until marking attached
previously to hose -arrow- coincides with shaft end.
Note
♦
The procedure when using a fuel extractor without shaft end
is basically the same.
♦
In this case, make a mark -arrow- on the extraction hose at
distance -a- = 980 mm from the end of the hose using insu‐
lating tape. The extraction hose has been properly inserted
when the affixed mark is level with the edge of the filler neck.
♦
If hose is difficult to insert, apply a thin coat of engine oil. DO
NOT use silicone-based lubricant.
– Drain fuel tank as much as possible through fuel filler neck.
– Carefully remove extraction hose.
– Remove fuel delivery unit ⇒ page 31 .
– Extract remaining fuel through opening for fuel delivery unit.
B - Procedure if fuel tank is less than 3/4 full
– Remove fuel delivery unit ⇒ page 31 .
– Extract fuel through opening for fuel delivery unit.
3.3 Removing and installing fuel tank with
attached components
Special tools and workshop equipment required
10 Rep. Gr.20 - Fuel supply system
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♦ Engine and gearbox jack -V.A.G 1383 A-
♦ Hose clip pliers -V.A.G 1921-
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
Removing
Observe safety precautions ⇒ page 1 .
Observe rules for cleanliness ⇒ page 2 .
– Release tank flap.
Caution
To prevent damage to the electronic components when dis‐
connecting the battery:
♦ Observe notes on procedure for disconnecting the battery.
– Disconnect battery ⇒ Rep. Gr. 27 .
WARNING
Risk of accident caused by weight of fuel tank
♦ Fuel tank must be empty when it is removed.
– Drain fuel tank ⇒ page 8 .
TT Coupé:
– Remove rear seat bench ⇒ Rep. Gr. 72 .
TT Roadster:
– Remove back panel side trim (right-side) ⇒ Rep. Gr. 70 .
3. Fuel tank - rest-of-world vehicles (front-wheel drive) 11
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
All vehicles (continued):
– Unscrew cover -1- for flange (right-side) -arrows-.
– Carefully release and unplug electrical connector -arrow-.
– Clean area around fuel filler neck.
– Remove filler cap from fuel filler neck.
– Remove centre and rear silencers ⇒ Rep. Gr. 26 .
– Remove rear axle ⇒ Rep. Gr. 42 .
– Remove rear right wheel housing liner ⇒ Rep. Gr. 66 .
– Remove cap nut -2- for earth wire and bolts -1- for fuel filler
neck.
WARNING
Risk of injury - fuel system operates under high pressure.
♦ To reduce the pressure in the fuel system, wrap a clean
cloth around the connection and carefully loosen the con‐
nection.
– Disconnect fuel return pipe -2- (blue), fuel supply pipe -1-
(black) and breather pipe -3- (white) from right front of fuel tank
by pressing release tabs.
12 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
– Position engine and gearbox jack -V.A.G 1383 A- below vehi‐
cle to support tank.
WARNING
Risk of accident caused by weight of fuel tank
♦ Fuel tank must be empty when it is removed.
– Loosen bolted connections -arrows-, starting with retaining lug
-arrow on bottom left-.
– Lower fuel tank with engine and gearbox jack -V.A.G 1383 A- .
Installing
• Tightening torques ⇒ page 6
Installation is carried out in the reverse order; note the following:
Note
Secure all hose connections with the correct type of hose clips
(same as original equipment) ⇒ Electronic parts catalogue .
Audi TT 1999 ➤
– Route earth connection as shown in illustration.
– Ensure that connector -2- for earth connection is properly
seated on metal ring -1- on fuel filler neck.
– Hook earth connection into two retainers -arrows- on fuel filler
neck.
Note
♦
For illustration purposes, the routing of the earth wire is shown
with the fuel tank removed.
♦
On some versions, only one retainer and a cable tie are fitted.
– Position fuel tank and securing straps on underside of vehicle
using engine and gearbox jack -V.A.G 1383 A- .
– Secure fuel tank at the points shown -arrows-. Tighten secur‐
ing straps first.
3. Fuel tank - rest-of-world vehicles (front-wheel drive) 13
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
– Check earth wiring at both ends for traces of oxidation and
remove oxidation if necessary.
– Tighten cap nut -2- for earth wire and bolts -1- for fuel filler
neck.
WARNING
Risk of explosion caused by electrostatic discharge.
♦ After installation, use an ohmmeter to check the electrical
connection between the metal ring on the fuel filler neck
and a bare metal part on the body:
• Specification: approx. 0 Ω
– Check installation position of rubber cup ⇒ page 5 .
– Install rear wheel housing liner ⇒ Rep. Gr. 66 .
– Install rear axle ⇒ Rep. Gr. 42 .
– Install exhaust system and align free of stress ⇒ Rep. Gr. 26 .
TT Coupé:
– Install rear seat bench ⇒ Rep. Gr. 72 .
TT Roadster:
– Install back panel side trim (right-side) ⇒ Rep. Gr. 70 .
All vehicles (continued):
– Connect battery. Observe notes on procedures required after
connecting battery ⇒ Rep. Gr. 27 .
14 Rep. Gr.20 - Fuel supply system
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
4 Fuel tank - USA vehicles (front-wheel
drive)
4.1 Fuel tank with attached components and fuel filler neck - exploded view
Fuel tank with attached components
1 - Securing strap
❑ Note different lengths
2 - Fuel filter
❑ Note correct position
❑ Installation position: Ar‐
row points in throughflow direction
3 - Fuel supply pipe
❑ Black
❑ To fuel rail
❑ Press release tab on
pipe connector to dis‐
connect
4 - Retaining clamp for fuel fil‐
ter
❑ Note installation posi‐
tion ⇒ page 19
5 - Breather pipe
❑ White
❑ From activated charcoal
filter to activated char‐
coal filter solenoid
valve 1 -N80-
6 - Fuel supply pipe
❑ Black
❑ To fuel filter
❑ Connect to connection
“V” on flange.
❑ Press release tab on
pipe connector to dis‐
connect
7 - Fuel return pipe
❑ Blue
❑ From fuel rail
❑ Connect to connection “R” on flange.
❑ Press release tab on pipe connector to disconnect
8 - Electrical connector
❑ For fuel system pressurisation pump -G6- and fuel gauge sender -G-
9 - Bolt
❑ 11 Nm
10 - Cap nut
❑ 10 Nm
4. Fuel tank - USA vehicles (front-wheel drive) 15
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
11 - Earth connection
❑ To eliminate electrostatic charge
❑ Installation position ⇒ page 18
❑ Ensure that connector is seated firmly on metal ring of fuel filler neck
❑ Secure contact terminal with cap nut -item 10❑ Test procedure after installing ⇒ page 18
12 - Nut
❑ 10 Nm
13 - Bracket
❑ For fuel filler neck
14 - Filler cap
❑ With seal
15 - Retaining ring
❑ Large diameter
16 - Retaining ring
❑ Small diameter
17 - Rubber cup
❑ With overflow hose
❑ Note installation position ⇒ page 5
18 - Breather pipe
❑ From gravity valve to activated charcoal filter
❑ Always remove and install together with gravity valve
19 - Breather pipe
❑ White
❑ From activated charcoal filter to activated charcoal filter solenoid valve 1 -N80-
20 - Fuel tank
❑ Removing and installing ⇒ page 21
21 - Heat shield
❑ For fuel tank
22 - Locking washer
❑ Removing: turn anti-clockwise
❑ 2 Nm
23 - Bolt
❑ 26 Nm
24 - Bolt
❑ 26 Nm
Filler neck
16 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
1 - Tank protector valve
❑ Clipped onto fuel filler
neck
❑ Closes breather pipe
when vacuum exists in
intake manifold
❑ Only remove together
with breather pipe and
gravity valve
2 - Breather valve
❑ Removing, installing
and checking
⇒ page 18
3 - O-rings
❑ Available in different
sizes
❑ Renew
4 - Seal
❑ Installation position:
sealing lip faces fuel fill‐
er neck
5 - O-ring
❑ Renew
6 - Gravity valve
❑ Only remove together
with breather pipe and
tank protector valve
❑ Checking ⇒ page 19
❑ To remove valve unclip
upwards out of filler
neck
7 - Earth connection
❑ To eliminate electrostatic charge
❑ Installation position ⇒ page 18
❑ Ensure that connector is seated firmly on metal ring of fuel filler neck
❑ Secure contact terminal with cap nut -item 8❑ Test procedure after installing ⇒ page 18
8 - Cap nut
❑ 10 Nm
9 - Breather pipe
❑ To activated charcoal filter
Audi TT 1999 ➤
4. Fuel tank - USA vehicles (front-wheel drive) 17
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
Installation position of earth connection
– Route earth connection as shown in illustration.
– Ensure that connector -2- for earth connection is properly
seated on metal ring -1- on fuel filler neck.
– Hook earth connection into the two retainers -arrows- on fuel
filler neck.
Note
♦
For illustration purposes, the routing of the earth wire is shown
with the fuel tank removed.
♦
On some versions, only one retainer and a cable tie are fitted.
Test procedure for earth connection
– Before securing, make sure that contact terminal -1- of wire
and cap nut -2- are free of corrosion to ensure proper earth
connection to body.
– Check that earth connection is properly secured at front re‐
tainer -arrow- on fuel filler neck.
WARNING
Risk of explosion caused by electrostatic discharge.
♦ After installation, use an ohmmeter to check the electrical
connection between the metal ring on the fuel filler neck
and a bare metal part on the body:
• Specification: approx. 0 Ω
Removing, installing and checking breather valve
Removing
– Removing fuel tank ⇒ page 21 .
– Unclip breather valve from side of filler neck.
– Press release tabs to detach hose connector.
Checking
– Blow into connection -2-:
• Button -1- in rest position: it should not be possible to blow
through valve.
• Button -1- pressed in direction of arrow: it should be possible
to blow through valve.
18 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
Removing, installing and checking gravity valve
Removing
Note
The gravity valve -1- can only be replaced together with tank pro‐
tector valve and breather pipe -3-.
– Removing fuel tank ⇒ page 21 .
– Unclip tank protector valve.
– Unclip gravity valve from filler neck and lift it off.
Checking
• Hold gravity valve in a vertical position: it should be possible
to blow through valve.
• Tilt gravity valve by 45°; it should not be possible to blow
through valve.
• Make sure O-ring -2- is not damaged.
Audi TT 1999 ➤
Installation position of retaining clamp for fuel filter
– Position retaining clamp as illustrated -arrow-.
Note
The illustration shows the installation position from the front.
4.2 Draining fuel tank
♦
♦
Special tools and workshop equipment required
♦ Fuel extractor unit -VAS 5190-
A - Procedure if fuel tank is more than 3/4 full ⇒ page 20 .
B - Procedure if fuel tank is less than 3/4 full ⇒ page 21 .
Procedure
Observe safety precautions ⇒ page 1 .
Observe rules for cleanliness ⇒ page 2 .
– Release tank flap.
4. Fuel tank - USA vehicles (front-wheel drive) 19
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
Caution
To prevent damage to the electronic components when dis‐
connecting the battery:
♦ Observe notes on procedure for disconnecting the battery.
– Disconnect battery ⇒ Rep. Gr. 27 .
WARNING
Risk of explosion caused by electrostatic discharge.
♦ Secure earth wire of fuel extractor unit -VAS 5190- to a
bare metal part on the body.
A - Procedure if fuel tank is more than 3/4 full
– Detach tapered adapter -2- from shaft end -1- of fuel extractor
unit -VAS 5190- .
– Use insulating tape to mark the extraction hose -arrow- at a
distance of -a- = 1045 mm from the end of the hose.
– Remove filler cap from fuel filler neck.
– Screw shaft end of fuel extractor unit -VAS 5190- onto fuel filler
neck.
20 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
Note
A ball valve -2- is located at the bottom of the filler neck in the fuel
tank -1-; it must not be damaged by the extraction hose -3-.
– Only push extraction hose into fuel tank until marking attached
previously to hose -arrow- coincides with shaft end.
Note
Audi TT 1999 ➤
♦
The procedure when using a fuel extractor without shaft end
is basically the same.
♦
In this case, make a mark -arrow- on the extraction hose at
distance -a- = 980 mm from the end of the hose using insu‐
lating tape. The extraction hose has been properly inserted
when the affixed mark is level with the edge of the filler neck.
♦
If hose is difficult to insert, apply a thin coat of engine oil. DO
NOT use silicone-based lubricant.
– Drain fuel tank as much as possible through fuel filler neck.
– Carefully remove extraction hose.
– Remove fuel delivery unit ⇒ page 31 .
– Extract remaining fuel through opening for fuel delivery unit.
B - Procedure if fuel tank is less than 3/4 full
– Remove fuel delivery unit ⇒ page 31 .
– Extract fuel through opening for fuel delivery unit.
4.3 Removing and installing fuel tank with
attached components
Special tools and workshop equipment required
4. Fuel tank - USA vehicles (front-wheel drive) 21
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
♦ Engine and gearbox jack -V.A.G 1383 A-
♦ Hose clip pliers -V.A.G 1921-
Removing
Observe safety precautions ⇒ page 1 .
Observe rules for cleanliness ⇒ page 2 .
– Release tank flap.
Caution
To prevent damage to the electronic components when dis‐
connecting the battery:
♦ Observe notes on procedure for disconnecting the battery.
– Disconnect battery ⇒ Rep. Gr. 27 .
WARNING
Risk of accident caused by weight of fuel tank
♦ Fuel tank must be empty when it is removed.
– Drain fuel tank ⇒ page 19 .
TT Coupé:
– Remove rear seat bench ⇒ Rep. Gr. 72 .
TT Roadster:
– Remove back panel side trim (right-side) ⇒ Rep. Gr. 70 .
22 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
All vehicles (continued):
– Unscrew cover -1- for flange (right-side) -arrows-.
– Carefully release and unplug electrical connector -arrow-.
– Clean area around fuel filler neck.
– Remove filler cap from fuel filler neck.
– Remove centre and rear silencers ⇒ Rep. Gr. 26 .
– Remove rear axle ⇒ Rep. Gr. 42 .
Audi TT 1999 ➤
– Remove bolts -1- and -2- from mountings of rear silencer.
– Remove heat shield for rear silencer -arrows-.
– Remove rear right wheel housing liner ⇒ Rep. Gr. 66 .
– Remove cap nut -2- for earth wire and bolts -1- for fuel filler
neck.
4. Fuel tank - USA vehicles (front-wheel drive) 23
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
WARNING
Risk of injury - fuel system operates under high pressure.
♦ To reduce the pressure in the fuel system, wrap a clean
cloth around the connection and carefully loosen the con‐
nection.
– Disconnect fuel return pipe -1- (blue), fuel supply pipe -2-
(black) and breather pipe -3- (white) from right front of fuel tank
by pressing release tabs.
Note
Do not detach pipe leading to fuel system diagnostic pump V144- .
– Disconnect breather pipes -1- and -2- leading to activated
charcoal filter.
– Position engine and gearbox jack -V.A.G 1383 A- below vehi‐
cle to support tank.
WARNING
Risk of accident caused by weight of fuel tank
♦ Fuel tank must be empty when it is removed.
– Loosen bolted connections -arrows-, starting with retaining lug
-arrow on bottom left-.
– Lower fuel tank with engine and gearbox jack -V.A.G 1383 A- .
Installing
• Tightening torques ⇒ page 15
Installation is carried out in the reverse order; note the following:
Note
Secure all hose connections with the correct type of hose clips
(same as original equipment) ⇒ Electronic parts catalogue .
24 Rep. Gr.20 - Fuel supply system
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.
Fuel supply system, petrol engines - Edition 06.2007
– Route earth connection as shown in illustration.
– Ensure that connector -2- for earth connection is properly
seated on metal ring -1- on fuel filler neck.
– Hook earth connection into two retainers -arrows- on fuel filler
neck.
Note
♦
For illustration purposes, the routing of the earth wire is shown
with the fuel tank removed.
♦
On some versions, only one retainer and a cable tie are fitted.
– Position fuel tank and securing straps on underside of vehicle
using engine and gearbox jack -V.A.G 1383 A- .
– Secure fuel tank at the points shown -arrows-. Tighten secur‐
ing straps first.
Audi TT 1999 ➤
– Check earth wiring at both ends for traces of oxidation and
remove oxidation if necessary.
– Tighten cap nut -2- for earth wire and bolts -1- for fuel filler
neck.
WARNING
Risk of explosion caused by electrostatic discharge.
♦ After installation, use an ohmmeter to check the electrical
connection between the metal ring on the fuel filler neck
and a bare metal part on the body:
• Specification: approx. 0 Ω
– Check installation position of rubber cup ⇒ page 5 .
– Install rear wheel housing liner ⇒ Rep. Gr. 66 .
– Install rear axle ⇒ Rep. Gr. 42 .
– Install exhaust system and align free of stress ⇒ Rep. Gr. 26 .
TT Coupé:
– Install rear seat bench ⇒ Rep. Gr. 72 .
TT Roadster:
– Install back panel side trim (right-side) ⇒ Rep. Gr. 70 .
All vehicles (continued):
– Connect battery. Observe notes on procedures required after
connecting battery ⇒ Rep. Gr. 27 .
4. Fuel tank - USA vehicles (front-wheel drive) 25
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.
Audi TT 1999 ➤
Fuel supply system, petrol engines - Edition 06.2007
5 Fuel delivery unit and fuel gauge
sender - all vehicles with front-wheel
drive
5.1 Fuel delivery unit and fuel gauge sender - exploded view
1 - Fuel delivery unit
❑ Checking fuel system
pressurisation pump G6- (electrical test)
⇒ page 27
❑ Checking residual pres‐
sure ⇒ Rep. Gr. 24
❑ Removing and installing
⇒ page 31
❑ Put at least 5 litres of
fuel into tank after instal‐
ling
2 - Seal
❑ Renew
❑ Fit dry seal in fuel tank
opening
3 - Fuel return pipe
❑ Blue
❑ From fuel rail
❑ Connect to connection
“R” on flange.
❑ Press release tab on
pipe connector to dis‐
connect
4 - Fuel supply pipe
❑ Black
❑ To fuel filter
❑ Connect to connection
“V” on flange.
❑ Press release tab on
pipe connector to dis‐
connect
5 - Electrical connector
❑ For fuel system pressurisation pump -G6- and fuel gauge sender -G-
6 - Union nut
❑ Loosen and tighten with union nut tool -3217❑ 80 Nm
7 - Fuel gauge sender -G-
❑ Checking resistance values ⇒ page 34
❑ Removing and installing ⇒ page 37
26 Rep. Gr.20 - Fuel supply system
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