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Fuel Supply System Audi TT 8N

Fuel System 84 illustrations ~14394 words

General repair notes

  1. Observe safety precautions. Refer to «Safety rules when working on fuel supply system»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Observe rules for cleanliness. Refer to «Rules of cleanliness»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__rules-of-cleanliness) .

Fuel Pump (FP) relay and activation, checking

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

The following steps should be taken before beginning work on the fuel supply

  1. Switch ignition off and disconnect battery Ground (GND) strap.
  2. Open fuel filler cap briefly and then close again.

When removing and installing components from full or partially full fuel tanks, the following must be observed

  1. Fuel tank may be only a maximum of 1/3 full.
  2. If necessary, remove fuel from tank as described - vehicles with Front Wheel Drive (FWD). Refer to «Fuel supply system components, servicing (vehicles with Front Wheel Drive)»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) , vehicles with All Wheel Drive (AWD), refer to «Fuel supply system components, servicing (vehicles with All Wheel Drive)»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  3. Before starting work, switch on exhaust extraction system and place an extraction hose close to the sensor opening in fuel tank to extract escaping fuel fumes. If no exhaust extraction system is available, a radial fan (as long as motor is not in air flow) with a displacement greater than 15 m3/h can be used.
  4. Prevent gasoline from contacting skin! Wear fuel-resistant gloves!

Before removal of complete fuel tank, tank must be emptied for weight considerations.

  1. If necessary, remove fuel from tank as described - vehicles with Front Wheel Drive (FWD). Refer to «Fuel supply system components, servicing (vehicles with Front Wheel Drive)»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) , vehicles with All Wheel Drive (AWD), refer to «Fuel supply system components, servicing (vehicles with All Wheel Drive)»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

Rules of cleanliness

When working on the fuel supply and/or injection system, pay careful attention to the following points

  1. Thoroughly clean all connections and the surrounding area before disconnecting.
  2. Place parts that have been removed on a clean surface and cover. Do not use fluffy cloths!
  3. Carefully cover opened compartments or seal, if the repair cannot be carried out immediately.
  4. Only install clean components: Only unpack replacement parts immediately prior to installation. Do not use parts that have been stored loose (in tool boxes etc.)
  1. When the system is open: Do not work with compressed air if it can be avoided. Do not move vehicle unless absolutely necessary.

Note. Secure all hose connections using same type of clips as originally installed

  1. VAG1921 Pliers are recommended for installing spring clips.
  2. Always replace seals and gaskets.
  3. Line up arrows on hose and tube connections.

Scheme 1

Scheme 1: Fuel tank with attachments, component overview
Scheme 1: Fuel tank with attachments, component overview

1 - Mounting straps

  1. Removing and installing. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-tank-with-attachments-removing-and)
  2. Note varying lengths

2 - Fuel filter

  1. Note installation position
  2. Installed position: arrow points in direction of flow

3 - Supply line

  1. Black
  2. To fuel rail
  3. To remove fuel filter, press release button at connection piece

4 - Screw clip

  1. For fuel filter
  2. Installed position. (Scheme 3)

5 - Vent line

  1. White
  2. From Evaporative Emission (EVAP) canister
  3. To EVAP canister purge regulator valve -N80

6 - Supply line

  1. Black
  2. To fuel filter
  3. Attaches to connection with "V.marking at connector flange
  4. Press release button on connector piece to remove from flange or from filter.

7 - Return line

  1. Blue
  2. From fuel rail
  3. Attaches to connection with "R" marking at connector flange
  4. To remove connector flange, press release button on connecting piece.

8 - 4-pin harness connector

9 - 11 Nm

10 - Cap nut, 10 Nm

11 - Ground (GND) connection

  1. Installed position/test requirements. (Scheme 2)
  2. Check for tight fit of connector at metal ring of filler tube.
  3. Securely tighten screw eyelet of electrical wire using cap nut item 14 under «Fuel tank with attachments, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system).
  4. After installing, check electrical connection of metal ring at fuel filler tube to a blank portion of chassis using multimeter
  1. Specified value: approx. 0 ohms

12 - Nut, 10 Nm

13 - Bracket

  1. For fuel filler tube

14 - Sealing cap

  1. With seal

15 - Tensioning ring

  1. Large diameter

16 - Tensioning ring

  1. Small diameter

17 - Rubber cup

  1. With overflow hose
  2. Installed position. Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

18 - Vent line

  1. To EVAP canister
  2. Only remove together with tank protection valve and gravity valve

19 - Vent line

  1. White
  2. From EVAP canister
  3. To Evaporative Emission (EVAP) canister purge regulator valve -N80

20 - Fuel tank

  1. Removing and installing. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-tank-with-attachments-removing-and)

21 - Heat shield

  1. For fuel tank

22 - Clamping washer

  1. Removing: turn to left
  2. Installing: tighten to 2 Nm

23 - 26 Nm

24 - 26 Nm

Scheme 2

Scheme 2: Installation position of Ground (GND) connection
Scheme 2: Installation position of Ground (GND) connection
  1. Route Ground (GND) connection (Scheme 2)
  2. Ensure connector -2- of Ground (GND) connection fits securely at metal ring -1- of fuel filler tube.
  3. Disconnect Ground (GND) connection at both retaining clips (arrow).

Note. Depending on construction version, a cable binder may be implemented in place of a clip.

Work sequence

  1. Tighten eyelet of electrical wire -1- at chassis using cap nut -2- (10 Nm).
  2. After installing, check electrical Ground connection using an ohmmeter between metal ring of fuel filler tube and chassis.
  1. Specified value 0 ohms

Scheme 3

Scheme 3: Installation position of screw clip for fuel filter
Scheme 3: Installation position of screw clip for fuel filter
  1. Install screw clip (arrow) as shown.

Note. Illustration depicts fuel filter from front.

Scheme 4

Scheme 4: Fuel filler tube, component overview
Scheme 4: Fuel filler tube, component overview

1 - Pressure retention valve

  1. Clipped to fuel filler unit
  2. Closes vent line when vacuum from intake manifold is present
  3. Only remove together with vent line and gravity valve

2 - Change-over valve

  1. Removing and installing, checking. (Scheme 5)

3 - O-rings

  1. Different sizes
  2. Always replace

4 - Seal

  1. Installed position: sealing lip faces fuel filler unit

5 - O-ring

  1. Always replace

6 - Gravity valve

  1. Only remove together with vent line and pressure retention valve
  2. Checking. See «Removing, installing, and checking gravity valve»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__removing-installing-and-checking-gravity-valve) , «Removing, installing, and checking gravity valve»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__removing-installing-and-checking-gravity-valve)
  3. To remove, unclip valve upward and lift out.

7 - Ground (GND) connection

  1. Installed position/check requirements. see scheme 7
  2. Ensure secure fit of connector at metal ring of fuel filler unit
  3. Securely tighten eyelet of electrical wire with cap nut. Refer to item 8 under «Fuel filler tube, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-filler-tube-component-overview).
  4. After installing, check electrical connection of metal ring at fuel filler tube to a blank portion of chassis using multimeter: Specified value: approx. 0 ohms

8 - Cap nut, 10 Nm

9 - Vent line

  1. To EVAP canister

Scheme 5

Scheme 5: Removing, installing, and checking change-over valve
Scheme 5: Removing, installing, and checking change-over valve

Removing

  1. Remove fuel tank. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-tank-with-attachments-removing-and) .
  2. Remove valve by unclipping sideways and remove from delivery unit.
  3. Remove hose by pressing release button.

Checking

  1. Blow into hose -2-.
  1. Button -1- at rest: it must not be possible to blow through hose.
  2. Button -1- pressed in direction of arrow: it must be possible to blow through hose.

Scheme 6

Scheme 6: Removing, installing, and checking gravity valve
Scheme 6: Removing, installing, and checking gravity valve

Removing

Note. Gravity valve -1- can only be replaced together with pressure retention valve and vent line -3-.

  1. Remove fuel tank. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-tank-with-attachments-removing-and) .
  2. Unclip pressure retention valve.
  3. To remove, unclip gravity valve upward and lift out.

Checking

  1. Hold valve in installation position.

It must be possible to blow through hose.

  1. Tilt valve 45°.

It must not be possible to blow through hose.

Note. O-ring -2- must not be damaged; replace if necessary.

Installation position of Ground (GND) connection

  1. Route Ground (GND) connection see scheme 7
  1. Ensure connector -2- of Ground (GND) connection fits securely at metal ring -1- of fuel filler tube.
  2. Disconnect Ground (GND) connection at both retaining clips (arrow).

Note. Depending on construction version, a cable binder may be implemented in place of a clip.

Work sequence

Scheme 7

Scheme 7
Scheme 7
  1. Tighten eyelet of electrical wire -1- at chassis using cap nut -2- (10 Nm).
  2. After installing, check electrical Ground connection using an ohmmeter between metal ring of fuel filler tube and chassis.
  1. Specified value 0 ohms

Fuel tank, emptying

A - Procedure for emptying fuel tank more than 3/4 full. Refer to A - Procedure for fuel tank more than 3/4 full .

B - Procedure for emptying fuel tank less than 3/4 full. Refer to B - Procedure for fuel tank less than 3/4 full .

Special tools and equipment

Scheme 8

Scheme 8: Fuel tank, emptying
Scheme 8: Fuel tank, emptying
  1. VAS 5190

or

Scheme 9

Scheme 9
Scheme 9
  1. VAG 1433 A

Work sequence

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

Scheme 10

Scheme 10
Scheme 10
  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).

Scheme 11

Scheme 11
Scheme 11
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

Scheme 12

Scheme 12
Scheme 12
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

Continued for all vehicles

WARNINGSecure VAG 1433 A or VAS 5190 Ground wire to a bare metal part on the body.

A - Procedure for fuel tank more than 3/4 full

  1. Remove filler cap from fuel tank filler neck.

Scheme 13

Scheme 13
Scheme 13
  1. Disconnect tapered adapter -2- from shaft end -1- of VAS 5190.
  2. Make a mark (arrow) on hose at distance a = 1465 mm from end of drain hose using insulating tape.

Scheme 14

Scheme 14
Scheme 14
  1. Fit shaft end -1- of fuel extractor VAS 5190 onto fuel tank filler neck.
  2. Push drain hose into fuel tank until marking on drain hose (arrow) coincides with shaft end.

Note. On the lower end of the fuel filler unit, there is a spherical valve -2- in the fuel tank -1-, which must not be excessively pressured or damaged via the siphoning hose -3-. Therefore, the hose should only be inserted to the marking (arrow).

  1. Remove fuel from tank as much as possible via fuel filler unit.
  2. Carefully remove siphoning hose.
  3. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing) .
  4. Siphon remaining fuel through opening for fuel pump.

Note. The procedure when using a fuel extractor without shaft end is basically the same. In this case make a mark on drain hose at distance a = 980 mm from end of drain hose using insulating tape. The drain hose is fitted properly when the marking on drain hose (arrow) coincides with rim of the filler neck. If the hose does not go in easily, lubricate lightly with engine oil. Never use lubricants containing silicone.

B - Procedure for fuel tank less than 3/4 full

  1. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing) .
  2. Siphon fuel through opening for fuel pump.

Fuel tank with attachments, removing and installing

Special tools and equipment

Scheme 15

Scheme 15: Fuel tank with attachments, removing and installing
Scheme 15: Fuel tank with attachments, removing and installing
  1. VAG1383A with VAG1359/2

Removing

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

Note. For weight reasons, fuel tank must be emptied for removal.

  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove the rear panel side trim.

Continued for all vehicles

Scheme 16

Scheme 16
Scheme 16
  1. Unscrew cover-1- at right (arrows).

Scheme 17

Scheme 17
Scheme 17
  1. Disengage 4-pin electrical harness connector (arrow) and remove carefully.
  2. Open fuel flap.
  3. Clean area surrounding fuel filler unit.
  4. Remove fuel filler cap from fuel filler unit.
  1. Remove rear axle.
  1. Remove center and rear muffler of exhaust system.

Refer to

  1. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-amu-bea) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): AMU, BEA
  2. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): ATC, AWP
  3. «26 - EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
  4. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276269-S01656351712008010300000) for 3.2 LITER V6 4V ENGINE MECHANICAL, ENGINE CODE(S): BHE

Scheme 18

Scheme 18
Scheme 18
  1. Remove mounts -1- and -2- for rear muffler.
  2. Remove heat shield for rear muffler (arrows).
  3. Remove right rear wheel housing liner.

Scheme 19

Scheme 19
Scheme 19
  1. Unscrew Ground (GND) wire -2- and screws -1- for fuel filler unit.
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

Scheme 20

Scheme 20
Scheme 20
  1. Disconnect return line -1- (blue), supply line -2- (black) and vent line -3- (white) front right at fuel tank (press release button).

Note. Electrical wire to Leak Detection Pump (LDP) -V144- will not be disconnected.

Scheme 21

Scheme 21
Scheme 21
  1. Disconnect vent lines -1- and -2- to EVAP canister.
  2. Place VAG1383A engine/transmission lifter under fuel tank for retrieval.
CAUTIONFor weight reasons, the fuel tank must be emptied for removal.

Scheme 22

Scheme 22
Scheme 22
  1. Loosen screws (arrows). Begin at retainer strap (lower left arrow).
  2. Lower fuel tank.

Installing

Installation is the reverse of removal, noting the following

Note. Secure all hose connections with the correct hose clamps (same as original equipment.

  1. To secure spring-loaded hose clamps, use hose clamp pliers VAG 1921.
  1. Check ground wiring at both ends for traces of oxidation. Remove any traces of oxidation if necessary.
  1. Route Ground (GND) wire as shown.
  2. Make sure connector -2- is seated properly on metal ring -1- of fuel filler opening.
  3. Engage Ground (GND) connection at both retaining clips (arrows).

Note. The illustration depicts Ground (GND) wire routing when fuel tank is removed. Depending on construction version, a cable binder may be implemented in place of a clip.

  1. Position fuel tank and mounting straps at vehicle floor using VAG1383A engine/transmission lifter.
  1. Secure fuel tank at mounting points (arrow) using bolts (26 Nm).
  2. Bolt mounting straps first.
  1. Tighten bolts -1- and screw on Ground (GND) connection -2-.
WARNINGAfter installing, check electrical Ground connection using ohm meter between fuel pump delivery unit and chassis. Specified value: 0 ohms
  1. Check installation position of rubber cup. Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Install rear right wheel housing liner and tighten fastening bolt for fuel filler neck
  1. Install and adjust (tension free) center and rear muffler of exhaust system.

Refer to

  1. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-amu-bea) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): AMU, BEA
  2. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): ATC, AWP
  3. «26 - EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
  4. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276269-S01656351712008010300000) for 3.2 LITER V6 4V ENGINE MECHANICAL, ENGINE CODE(S): BHE
  5. «26 - EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276276-S21462548962008010300000) for 3.2 LITER V6 4V GENERIC SCAN TOOL, ENGINE CODE: BHE
  1. Install rear axle

Note. After connecting battery, be sure to activate the electrical accessories (radio, clock, power windows). Additional precautions for reconnecting the power supply

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «01 - ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP

Tightening torques

ComponentNm
Mounting straps for fuel tank to chassis26
Fuel tank to chassis26
Fuel filler unit to bracket11
Ground (GND) wire at wheel housing10
Battery terminal to battery post5

Scheme 23

Scheme 23: Tank flap, component overview
Scheme 23: Tank flap, component overview

1 - Tensioning ring

  1. Small diameter

2 - Tensioning ring

  1. Large diameter

3 - Sealing cap

  1. With seal

4 - O-ring

  1. Replace if damaged

5 - Tank flap

  1. Removing and installing. Refer to «Removing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

6 - Cylinder bolt, 4 Nm

  1. To remove tank flap, remove only three illustrated bolts. Refer to «Removing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

7 - O-ring

  1. Replace if damaged

8 - Striker

9 - Compression spring

10 - Retaining plate

11 - Phillips-head screw

12 - Disengagement cable

13 - Rubber cup

  1. With overflow hose

14 - Fuel filler unit

Tank flap, removing and installing

Special tools and equipment

Scheme 24

Scheme 24: Tank flap, removing and installing
Scheme 24: Tank flap, removing and installing
  1. 3370 special tool

Scheme 25

Scheme 25: Removing
Scheme 25: Removing
  1. Remove three bolts designated with arrows.
  2. Remove tank flap vertically from chassis cut-out using special tool 3370.

Scheme 26

Scheme 26
Scheme 26
  1. Remove bolts (arrows) of release cable.

Installation is the reverse of removal, noting the following

Scheme 27

Scheme 27: Installing
Scheme 27: Installing
  1. In order to route overflow hose without kinks, rubber cup must be installed as follows
  2. The edge of the overflow hole must be flush with the edge of the square hole as depicted (arrows).
ComponentNm
Tank flap to body4

Scheme 28

Scheme 28: Fuel pump and Fuel level sensor -G-, component overview
Scheme 28: Fuel pump and Fuel level sensor -G-, component overview

1 - Fuel pump

  1. Removing and installing. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing)
  2. Check Fuel Pump (FP) electrically. Refer to «Fuel pump, electrical testing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-electrical-testing)
  3. Checking residual pressure

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

2 - Seal

  1. Always replace
  2. To install, place into opening of fuel tank when dry.

3 - Return line

  1. Blue
  2. From fuel rail
  3. Attaches to connection with "R" marking at connector flange
  4. To remove connector flange, press release button on connecting piece

4 - Supply line

  1. Black
  2. To fuel filter
  3. Attaches to connection with "V.marking at connector flange
  4. To remove from connector flange or from filter, press release button on connecting piece.

5 - 4-pin harness connector

  1. For Fuel Pump (FP) and Fuel level sensor -G

6 - Union nut, 80 Nm

  1. Use ring nut spanner 3217 to remove and install

7 - Fuel level sensor -G

  1. Checking resistance values. Refer to «Fuel level sensor -G-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-level-sensor-g-checking)
  2. Removing and installing. Refer to «Fuel level sensor -G-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-level-sensor-g-removing-and)

Scheme 29

Scheme 29: Fuel pump, electrical testing
Scheme 29: Fuel pump, electrical testing

Special tools and equipment

  1. Ring nut spanner 3217
  2. VAG1348/3A Remote control
  3. VAG1348/3-2 Adapter
  4. VAG1526A Multimeter
  1. VAG1594A Adapter set

Requirements

  1. Battery voltage at least 12.7 V
  2. Fuse S228 OK (position 28)

Scheme 30

Scheme 30
Scheme 30
  1. Relay 4 in micro-central electrics (in driver's footwell, left) OK
  2. Fuel filter OK
  3. Ignition switched off

Work sequence

  1. Open cover of fuse box at left side of instrument panel.
  2. Remove fuse S228 at fuse carrier (position 28, left row, 5th large fuse from top).

Scheme 31

Scheme 31
Scheme 31
  1. Connect VAG1348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of socket from fuse -S228- (arrow).
  2. Connect clamping terminal to B+.
  3. Press switch of remote control.

Noise of pump must be audible.

Note. Fuel Pump (FP) runs quietly. Surrounding noise should be avoided during test of the Fuel Pump (FP).

If no noise can be heard

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disengage 4-pin electrical harness connector and remove (arrow).

Scheme 32

Scheme 32
Scheme 32
  1. Connect multimeter between terminal 1 and 4 of harness connector for voltage measurement.
  2. Press switch of remote control.

Specification: approx. battery voltage

If specified value is not obtained

  1. Locate and repair open circuit using wiring diagram.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

If specified value is obtained, although no operating noise can be heard from pump

  1. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing) .
  2. Check whether electrical wires between flange and Fuel Pump (FP) are connected, and test for continuity if necessary.

If no malfunctions are found in wires

  1. Fuel Pump (FP) is faulty. Replace fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing) .

Fuel pump delivery quantity, checking

Special tools and equipment

Scheme 33

Scheme 33: Fuel pump delivery quantity, checking
Scheme 33: Fuel pump delivery quantity, checking
  1. VAG1348/3A with VAG1348/3-2

Scheme 34

Scheme 34
Scheme 34
  1. VAG1318/17
  2. Measuring container safe for fuel

Requirements

  1. Battery voltage at least 12.7 V
  2. Fuel filter OK
  3. Switch ignition off

Work sequence

  1. Open cover of fuse box at left side of instrument panel.
  2. Remove fuse -S228- at fuse carrier (position 28, left row, 5th large fuse from top).
  1. Connect VAG1348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of socket from fuse -S228- (arrow).
  2. Connect clamping terminal to Battery +.
  3. Remove fuel filler cap from fuel filler unit.

Scheme 35

Scheme 35
Scheme 35
  1. Remove screw -1- and remove coolant expansion tank cover (arrow).
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

Scheme 36

Scheme 36
Scheme 36
  1. Disconnect fuel return line -1- from line tube -2- (press release button).
  2. Connect VAG1318/17 adapter to fuel return line from engine and hold in a measuring container.
  3. Operate remote control for 15 seconds (keep button pressed).

Scheme 37

Scheme 37
Scheme 37
  1. Compare fuel quantity pumped with specified value.

*) Smallest quantity cm3/15 s

**) Voltage at fuel pump with engine off and pump running (approx. 2 volts less than battery voltage).

Fuel pump, removing and installing

Special tools and equipment

Scheme 38

Scheme 38: Fuel pump, removing and installing
Scheme 38: Fuel pump, removing and installing
  1. Ring nut spanner 3217
  1. Observe safety precautions. Refer to «Safety rules when working on fuel supply system»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Observe rules for cleanliness. Refer to «Rules of cleanliness»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__rules-of-cleanliness) .
WARNINGFuel tank must be less than 1/3 full when removing fuel pump. If necessary,empty fuel tank. Refer to Fuel tank, emptying
  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disengage 4-pin electrical harness connector and remove (arrow).
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

Scheme 39

Scheme 39
Scheme 39
  1. Disconnect fuel supply line -1- and fuel return line -2- (press release button).
WARNINGFuel tank must be less than 1/3 full when removing fuel pump. If necessary, empty fuel tank. Refer to Fuel tank, emptying

Scheme 40

Scheme 40
Scheme 40
  1. Use ring nut spanner 3217 to remove union nut.
  2. Pull fuel pump and sealing ring from opening of fuel tank.

Note. If Fuel Pump (FP) is still full of fuel, empty fuel before replacing.

Installation is the reverse of removal, noting the following

Note. Insert new, dry seal for connection flange into opening of fuel container. When inserting Fuel Pump (FP) into fuel tank, be sure not to bend fuel level sensor. Make sure fuel hose is securely fastened.

Scheme 41

Scheme 41: Installing
Scheme 41: Installing
  1. Press connecting flange down against spring pressure and bring connecting flange into proper installation position.
  1. Marking on connecting flange must align with marking on fuel tank (arrows).
  1. Apply union nut by hand.
  1. Use ring nut spanner 3217 to tighten union nut (80 Nm).
  1. Connect fuel lines.
  1. Black supply line -1- to connection with identification -V-.
  2. Blue return line -2- to connection with identification -R-.
  1. Connect 4-pin harness connector.

Note. After connecting battery, be sure to activate the electrical accessories (radio, clock, power windows). Additional precautions for reconnecting the power supply

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «01 - ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
ComponentNm
Union nut for Fuel Pump (FP)80
Battery terminal to battery post5

Fuel level sensor -G-, checking

Special tools and equipment

Scheme 42

Scheme 42: Fuel level sensor -G-, checking
Scheme 42: Fuel level sensor -G-, checking
  1. VAG1526A Multimeter

Scheme 43

Scheme 43
Scheme 43
  1. VAG1594A Adapter set

Work sequence

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disconnect 4-pin electrical harness connector (arrow).

Vehicles up to 05.02

Scheme 44

Scheme 44
Scheme 44
  1. Connect multimeter between terminal 2 and 3 for resistance measurement.
ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -GApprox. 57 ohmsApprox. 290 ohms
  1. For measured value 0 ohms there is a short circuit
  2. For measured value infinity ohms there is an open circuit.

Note. To check resistance values "tank full" or "tank empty", Fuel Pump (FP) must be removed (Refer to Fuel pump, removing and installing ) and the sensor float must be placed in the upper or lower end position.

With fuel level sensor removed, the following values will result due to the longer reach of the float arm

ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -GApprox. 54 ohmsApprox. 290 ohms

Vehicles from 05.02

  1. Connect multimeter between terminal 2 and 3 for resistance measurement.
ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -GApprox. 290 ohmsApprox. 57 ohms
  1. For measured value 0 ohms there is a short circuit
  2. For measured value infinity ohms there is an open circuit.

Note. To check resistance values "tank full" or "tank empty", Fuel Pump (FP) must be removed (Refer to Fuel pump, removing and installing ) and the sensor float must be placed in the upper or lower end position.

With fuel level sensor removed, the following values will result due to the longer reach of the float arm

ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -GApprox. 290 ohmsApprox. 54 ohms

Fuel level sensor -G-, removing and installing

Removing

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

  1. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-pump-removing-and-installing) .

Scheme 45

Scheme 45
Scheme 45
  1. Disengage connector prongs of electrical wires -3- and -4- and disconnect.
  2. Pry off retaining straps -1- and -2- using screwdriver and remove fuel level sensor toward bottom (arrow).

Installing

Installation is the reverse of removal, noting the following

  1. Insert fuel level sensor into guides at Fuel Pump (FP) and press up until engagement.
  2. Insert connector prongs of electrical wires and check for proper engagement.
  3. Install Fuel Pump (FP). Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  4. Observe notes for connection of battery.

Note. Secure all hose connections using same type of clips as originally installed: VAG1921 Pliers are recommended for installing spring clips. Always replace seals and gaskets. Line up arrows on hose and tube connections.

Scheme 46

Scheme 46: Fuel tank with attachments, component overview
Scheme 46: Fuel tank with attachments, component overview

1 - Heat shield

  1. For fuel tank
  2. With strap

2 - Fuel filter

  1. Note installation position
  2. Installed position: arrow points in direction of flow

3 - Supply line

  1. Black
  2. To fuel rail
  3. To remove fuel filter, press release button at connection piece

4 - Screw clip

  1. For fuel filter
  2. Installed position. see scheme 71

5 - Vent line

  1. White
  2. From Evaporative Emission (EVAP) canister
  3. To EVAP canister purge regulator valve -N80

6 - Supply line

  1. Black
  2. To fuel filter
  3. Attaches to connection with "V.marking at connector flange
  4. Press release button on connector piece to remove from flange or from filter.

7 - Return line

  1. Blue
  2. From fuel rail
  3. Attaches to connection with "R" marking at connector flange
  4. To remove connector flange, press release button on connecting piece.

8 - 4-pin harness connector

9 - 11 Nm

10 - Cap nut, 10 Nm

11 - Ground (GND) connection

  1. Installed position/test requirements. see scheme 69
  2. Check for tight fit of connector at metal ring of filler tube.
  3. Securely tighten screw eyelet of electrical wire using cap nut item 14 under «Fuel tank with attachments, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system).
  4. After installing, check electrical connection of metal ring at fuel filler tube to a blank portion of chassis using multimeter
  1. Specified value: approx. 0 ohms

12 - Nut, 10 Nm

13 - Bracket

  1. For fuel filler tube

14 - Sealing cap

  1. With seal

15 - Tensioning ring

  1. Large diameter

16 - Tensioning ring

  1. Small diameter

17 - Rubber cup

  1. With overflow hose
  2. Installed position. see scheme 68

18 - Vent line

  1. White
  2. From EVAP canister
  3. To Evaporative Emission (EVAP) canister purge regulator valve -N80

19 - Vent line

  1. To EVAP canister
  2. Only remove together with tank protection valve and gravity valve

20 - Fuel tank

  1. Removing and installing. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

21 - 26 Nm

22 - Mounting straps

  1. Removing and installing. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)
  2. Note varying lengths

23 - 26 Nm

24 - Clamping washer

  1. Removing: turn to left
  2. Installing: tighten to 2 Nm

25 - 26 Nm

  1. Route Ground (GND) connection see scheme 69
  2. Ensure connector -2- of Ground (GND) connection fits securely at metal ring -1- of fuel filler tube.
  3. Disconnect Ground (GND) connection at both retaining clips(arrow).

Note. Depending on construction version, a cable binder may be implemented in place of a clip.

Work sequence

  1. Tighten eyelet of electrical wire -1- at chassis using cap nut -2- (10 Nm).
  2. After installing, check electrical Ground connection using an ohmmeter between metal ring of fuel filler tube and chassis.
  1. Specified value 0 ohms

Installation position of screw clip for fuel filter

  1. Install screw clip (arrow) as shown.

Note. Illustration depicts fuel filter from front.

Fuel filler tube, component overview

1 - Pressure retention valve

  1. Clipped to fuel filler unit
  2. Closes vent line when vacuum from intake manifold is present
  3. Only remove together with vent line and gravity valve

2 - Vent valve

  1. Removing and installing, checking. see scheme 73

3 - O-rings

  1. Different sizes
  2. Always replace

4 - Seal

  1. Installed position: sealing lip faces fuel filler unit

5 - O-ring

  1. Always replace

6 - Gravity valve

  1. Only remove together with vent line and pressure retention valve
  2. Checking. (Scheme 6)
  3. To remove, unclip valve upward and lift out.

7 - Ground (GND) connection

  1. Installed position/check requirements. see scheme 75
  2. Ensure secure fit of connector at metal ring of fuel filler unit
  3. Securely tighten eyelet of electrical wire with cap nut. Refer to item 8 under «Fuel filler tube, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-filler-tube-component-overview).
  4. After installing, check electrical connection of metal ring at fuel filler tube to a blank portion of chassis using multimeter: Specified value: approx. 0 ohms

8 - Cap nut, 10 Nm

9 - Vent line

  1. To EVAP canister

Removing, installing, and checking change-over valve

Removing

  1. Remove fuel tank. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Remove valve by unclipping sideways and remove from delivery unit.
  3. Remove hose coupling by pressing release button.

Checking

  1. Blow into hose -2-.
  1. Button -1- at rest: it must not be possible to blow through hose.
  2. Button -1- pressed in direction of arrow: it must be possible to blow through hose.

Removing, installing, and checking gravity valve

Removing

Note. Gravity valve -1- can only be replaced together with pressure retention valve and vent line -3-.

  1. Remove fuel tank. Refer to «Fuel tank with attachments, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Unclip pressure retention valve.
  3. To remove, unclip gravity valve upward and lift out.

Checking

  1. Hold valve in installation position.

It must be possible to blow through hose.

  1. Tilt valve 45°.

It must not be possible to blow through hose.

Note. O-ring -2- must not be damaged; replace if necessary.

  1. Route Ground (GND) connection see scheme 75
  1. Ensure connector -2- of Ground (GND) connection fits securely at metal ring -1- of fuel filler tube.
  2. Disconnect Ground (GND) connection at both retaining clips(arrow).

Note. Depending on construction version, a cable binder may be implemented in place of a clip.

Work sequence

  1. Tighten eyelet of electrical wire -1- at chassis using cap nut -2- (10 Nm).
  2. After installing, check electrical Ground connection using an ohmmeter between metal ring of fuel filler tube and chassis.
  1. Specified value 0 ohms

A - Procedure for emptying fuel tank more than 1/3 full. Refer to A - Procedure for fuel tank more than 1/3 full .

B - Procedure for emptying fuel tank less than 1/3 full. Refer to B - Procedure for fuel tank less than 1/3 full .

Special tools and equipment

  1. VAS 5190

or

  1. VAG 1433 A

Work sequence

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

Continued for all vehicles

WARNINGSecure VAG 1433 A or VAS 5190 Ground wire to a bare metal part on the body.

A - Procedure for fuel tank more than 1/3 full

  1. Remove filler cap from fuel tank filler neck.
  1. Disconnect tapered adapter -2- from shaft end -1- of VAS 5190.
  2. Make a mark (arrow) on hose at distance a = 1415 mm from end of drain hose using insulating tape.
  1. Fit shaft end -1- of fuel extractor VAS 5190 onto fuel tank filler neck.
  2. Push drain hose into fuel tank until marking on drain hose (arrow) coincides with shaft end.

Note. On the lower end of the fuel filler unit, there is a spherical valve -2- in the fuel tank -1-, which must not be excessively pressured or damaged via the siphoning hose -3-. Therefore, the hose should only be inserted to the marking (arrow).

  1. Remove fuel from tank as much as possible via fuel filler unit.
  2. Carefully remove siphoning hose.
  3. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  4. Siphon remaining fuel in right chamber of fuel tank through opening for fuel pump.
  1. Insert hose in left chamber of fuel tank and siphon remaining fuel.

Note. The procedure when using a fuel extractor without shaft end is basically the same.

Scheme 47

Scheme 47
Scheme 47
  1. In this case make a mark on drain hose at distance a = 1350 mm from end of drain hose using insulating tape. The drain hose is fitted properly when marking on drain hose (arrow) coincides with rim of filler neck.
  2. If the hose does not go in easily, lubricate lightly with engine oil. Never use lubricants containing silicone.

B - Procedure for fuel tank less than 1/3 full

  1. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Siphon remaining fuel in right chamber of fuel tank through opening for fuel pump.
  3. Insert hose in left chamber of fuel tank and siphon remaining fuel.

Special tools and equipment

  1. VAG1383A Engine/transmission jack with VAG1359/2

Removing

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

Note. For weight reasons, fuel tank must be emptied for removal.

  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover-1- at right (arrows).

Scheme 48

Scheme 48
Scheme 48
  1. Disengage 4-pin electrical harness connector (arrow) and remove.
  2. Open fuel flap.
  3. Clean area surrounding fuel filler unit.
  4. Remove fuel filler cap from fuel filler unit.
  1. Remove center and rear muffler of exhaust system

Refer to

  1. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-amu-bea) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): AMU, BEA
  2. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): ATC, AWP
  3. «26 - EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
  4. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276269-S01656351712008010300000) for 3.2 LITER V6 4V ENGINE MECHANICAL, ENGINE CODE(S): BHE
  5. «26 - EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276276-S21462548962008010300000) for 3.2 LITER V6 4V GENERIC SCAN TOOL, ENGINE CODE: BHE
  1. Remove driveshaft
  1. Remove rear axle
  1. Remove right rear wheel housing liner
  1. Unscrew Ground (GND) wire -2- and screws -1- for fuel filler unit.
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  1. Disconnect return line -1- (blue), supply line -2- (black) and vent line -3- (white) front right at fuel tank (press release button).

Note. Electrical wire to Leak Detection Pump (LDP) -V144- will not be disconnected.

Scheme 49

Scheme 49
Scheme 49
  1. Disconnect vent lines -1- and -2- to EVAP canister.
  2. Place VAG1383A engine/transmission lifter under fuel tank for retrieval.
WARNINGFor weight reasons, fuel tank must be emptied for removal.

Scheme 50

Scheme 50
Scheme 50
  1. Loosen screws as follows
  1. Retaining tabs -1- and -5-.
  2. Carrier panel -3- and -7-.
  3. Mounting straps -2-, -4-, -6- and -8-.
  1. Lower fuel tank.

Installing

Installation is the reverse of removal, noting the following

Note. Secure all hose connections with the correct hose clamps (same as original equipment. To secure spring-loaded hose clamps, use hose clamp pliers VAG 1921.

  1. Check ground wiring at both ends for traces of oxidation. Remove any traces of oxidation if necessary.
  1. Route Ground (GND) wire as shown.
  2. Make sure connector -2- is seated properly on metal ring -1- of fuel filler opening.
  3. Engage Ground (GND) connection at both retaining clips (arrows).

Note. The illustration depicts Ground (GND) wire routing when fuel tank is removed. Depending on construction version, a cable binder may be implemented in place of a clip.

  1. Position fuel tank with carrying sheet and mounting straps at vehicle floor using VAG1383A engine/transmission lifter.
  1. Secure fuel tank using bolts as follows
  1. Mounting straps -2-, -4-, -6- and -8-.
  2. Carrier panel -3- and -7-.
  3. Retaining tabs -1- and -5-.
  1. Tighten bolts -1- and screw on Ground (GND) connection -2-.
WARNINGAfter installing, check electrical Ground connection using ohm meter between fuel pump delivery unit and chassis. Specified value: 0 ohms
  1. Check installation position of rubber cup. Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Install rear right wheel housing liner and tighten fastening bolt for fuel filler neck
  1. Install driveshaft
  1. Install rear axle
  1. Install and adjust (tension free) center and rear muffler of exhaust system.

Refer to

  1. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-amu-bea) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): AMU, BEA
  2. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): ATC, AWP
  3. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276269-S01656351712008010300000) for 3.2 LITER V6 4V ENGINE MECHANICAL, ENGINE CODE(S): BHE

Note. After connecting battery, be sure to activate the electrical accessories (radio, clock, power windows). Additional precautions for reconnecting the power supply

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

Tightening torques

ComponentNm
Mounting straps for fuel tank to chassis26
Fuel tank to chassis26
Fuel filler unit to bracket11
Ground (GND) wire at wheel housing10
Battery terminal to battery post5

Tank flap, component overview

1 - Tensioning ring

  1. Small diameter

2 - Tensioning ring

  1. Large diameter

3 - Sealing cap

  1. With seal

4 - O-ring

  1. Replace if damaged

5 - Tank flap

  1. Removing and installing. Refer to «Removing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

6 - Cylinder bolt - 4 Nm

  1. To remove tank flap, remove only three illustrated bolts. Refer to «Removing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

7 - O-ring

  1. Replace if damaged

8 - Striker

9 - Compression spring

10 - Retaining plate

11 - Phillips-head screw

12 - Disengagement cable

13 - Rubber cup

  1. With overflow hose

14 - Fuel filler unit

Special tools and equipment

  1. 3370 special tool
  1. Remove three bolts designated with arrows.
  2. Remove tank flap vertically from chassis cut-out using special tool 3370.
  1. Remove bolts (arrows) of disengagement cable.

Installation is the reverse of removal, noting the following

  1. In order to route overflow hose without kinks, rubber cup must be installed as follows
  2. The edge of the overflow hole must be flush with the edge of the square hole as depicted (arrows).
ComponentNm
Tank flap to body4

Scheme 51

Scheme 51: Fuel pump, Fuel level sensor -G- and Fuel level sensor 2 -G169-, component overview
Scheme 51: Fuel pump, Fuel level sensor -G- and Fuel level sensor 2 -G169-, component overview

1 - Fuel level sensor -G

  1. Checking resistance values. Refer to «Fuel level sensor -G-/Fuel level sensor 2-G169-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-level-sensor-g-fuel-level-sensor)
  2. Removing and installing. Refer to «Fuel level sensor -G-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

2 - Fuel pump

  1. Removing and installing. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)
  2. Check Fuel Pump (FP) electrically. Refer to «Fuel pump, electrical testing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  3. Checking residual pressure

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

3 - Seal

  1. Always replace
  2. To install, place into opening of fuel tank when dry.

4 - Return line

  1. Blue
  2. From fuel rail
  3. Attaches to connection with "R" marking at connector flange
  4. To remove connector flange, press release button on connecting piece

5 - Supply line

  1. Black
  2. To fuel filter
  3. Attaches to connection with "V.marking at connector flange
  4. To remove from connector flange or from filter, press release button on connecting piece.

6 - 4-pin harness connector

  1. For Fuel Pump (FP), Fuel level sensor -G- and Fuel level sensor 2 -G169

7 - Union nut, 80 Nm

  1. Use ring nut spanner 3217 to remove and install

8 - 2-pin harness connector

  1. For Fuel level sensor 2 -G169

9 - Union nut, 80 Nm

  1. Use ring nut spanner 3217 to remove and install

10 - Seal

  1. Always replace
  2. To install, place into opening of fuel tank when dry.

11 - Secondary fuel pump

  1. With connecting flange
  2. With wiring
  3. Removing and Installing. Refer to «Secondary fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__secondary-fuel-pump-removing-and-installing)

12 - Fuel level sensor 2 -G169

  1. Checking. Refer to «Fuel level sensor -G-/Fuel level sensor 2-G169-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__fuel-level-sensor-g-fuel-level-sensor)
  2. Removing and installing. Refer to «Fuel level sensor -G-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

13 - Hose coupling

  1. For fuel hose to secondary fuel pump
  2. To disconnect, press release button

14 - Retaining strap

  1. For fuel hose from secondary fuel pump
  2. Engage in fuel pump and press in locking mechanism

Fuel pump, electrical testing

Special tools and equipment

  1. Ring nut spanner 3217
  2. VAG1348/3-2 Adapter
  3. VAG1348/3A Adapter
  4. VAG1526A Multimeter
  1. VAG1594A Adapter kit

Requirements

  1. Battery voltage at least 12.7 V
  2. Fuse -S228- OK (position 28)
  1. Relay 4 in micro-central electrics (in driver's footwell, left) OK
  2. Fuel filter OK
  3. Ignition switched off

Work sequence

  1. Open cover of fuse box at left side of instrument panel.
  2. Remove fuse -S228- at fuse carrier (position 28, left row, 5th large fuse from top).
  1. Connect VAG1348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of socket from fuse -S228- (arrow).
  2. Connect clamping terminal to Battery +.
  3. Press switch of remote control.

Pump noise must be audible.

Note. Fuel Pump (FP) runs quietly. Surrounding noise should be avoided during test of the Fuel Pump (FP).

If no noise can be heard

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disengage 4-pin electrical harness connector and remove (arrow).
  1. Connect multimeter between terminal 1 and 4 of harness connector for voltage measurement.
  2. Press switch of remote control.

Specification: approx. battery voltage

If specified value is not obtained

  1. Locate and repair open circuit using wiring diagram.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

If specified value is obtained, although no operating noise can be heard from pump, remove connecting flange as follows

  1. When removing the connection flange from the fuel pump, the fuel tank should be less than 1/3 full. If necessary, empty the fuel tank. Refer to «Fuel tank, emptying»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  1. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

Continued for all vehicles

WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

Scheme 52

Scheme 52
Scheme 52
  1. Disconnect fuel supply line -1- and fuel return line -2- (press release button).
WARNINGFuel tank must be less than 1/3 full when removing fuel pump. If necessary,empty fuel tank. Refer to Fuel tank, emptying
  1. Use ring nut spanner 3217 to remove and install
  2. Remove connecting flange of fuel pump via opening of fuel tank and lay aside with wires connected.
  3. Check whether electrical wires between flange and Fuel Pump (FP) are connected, check for continuity if necessary.

If no malfunctions are found in wires

  1. Fuel Pump (FP) is faulty; replace fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

Special tools and equipment

  1. VAG1348/3A with VAG1348/3-2 Adapter
  1. VAG1318/17 Adapter
  2. Measuring container safe for fuel

Requirements

  1. Battery voltage at least 12.7 V
  2. Fuel filter OK
  3. Switch ignition off

Work sequence

  1. Open cover of fuse box at left side of instrument panel.
  2. Remove fuse -S228- at fuse carrier (position 28, left row, 5th large fuse from top).
  1. Connect VAG1348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of socket from fuse -S228- (arrow).
  2. Connect clamping terminal to Battery +.
  3. Remove fuel filler cap from fuel filler unit.
  1. Remove screw -1- and remove coolant expansion tank cover (arrow).
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  1. Disconnect fuel return line -1- from -2- (press release button).
  2. Connect VAG1318/17 adapter to fuel return line from engine and hold in a measuring container.
  3. Operate remote control for 15 seconds (keep button pressed).
  1. Compare fuel quantity pumped with specified value.

*) Smallest quantity cm3/15 s

**) Voltage at fuel pump with engine off and pump running (approx. 2 volts less than battery voltage).

Special tools and equipment

  1. Ring nut spanner 3217

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

When removing the connection flange from the fuel pump, the fuel tank should be less than 1/3 full.

  1. If necessary, empty fuel tank. Refer to «Fuel tank, emptying»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Note radio code (for vehicles with coded anti-theft radio). Obtain if necessary.

Vehicles with 4-cylinder engine

  1. If installed, remove cover above battery.
  2. Open battery protective casing (Velcro).
  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow).

Vehicles with 6-cylinder engine

  1. Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disengage 4-pin electrical harness connector and remove (arrow).
WARNINGFuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  1. Disconnect fuel supply line -1- and fuel return line -2- (press release button).
WARNINGFuel tank must be less than 1/3 full when removing fuel pump.
  1. Use ring nut spanner 3217 to remove union nut.
  2. Pull fuel pump and sealing ring out of opening in fuel tank and set aside with lines attached.

Scheme 53

Scheme 53
Scheme 53
  1. Reach into fuel tank and disconnect harness connector -1-.
  2. Press release button of hose coupling and disconnect wire -2-.
  3. Pull retaining strap -3- upward and disengage strap and wire -4- to fuel pump -5-.

Note. Fuel pump is shown in removed condition in (Scheme 54).

  1. Pull fuel pump and sealing ring out of opening in fuel tank.

Installation is the reverse of removal, noting the following

Note. Insert new, dry seal for connection flange into opening of fuel container. When inserting Fuel Pump (FP) into fuel tank, be sure not to bend fuel level sensor. Make sure fuel hose is securely fastened.

  1. Insert Fuel Pump (FP) -5- in connecting flange of fuel tank (set aside).
  2. Engage retaining strap -3- of wire -4- to Fuel Pump and press retaining strap into locking mechanism.
  1. Retaining strap must engage properly
  1. Press hose coupling of wire -2- together until engagement.
  2. Connect 2-pin harness connector -1- to fuel level sensor.
  3. Insert guide of connecting flange into guide of Fuel Pump (FP). Be careful of spring.

Scheme 54

Scheme 54
Scheme 54
  1. Press connecting flange down against spring pressure and bring connecting flange into proper installation position.
  1. Marking on connecting flange must align with marking on fuel tank (arrows).
  1. Apply union nut by hand.
  1. Use ring nut spanner 3217 to tighten union nut.
  1. Attach fuel line.
  1. Black supply line -1- to connection with identification -V-.
  2. Blue return line -2- to connection with identification -R-.
  1. Connect 4-pin harness connector.

Note. After connecting battery, be sure to activate the electrical accessories (radio, clock, power windows). Additional precautions for reconnecting the power supply

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
ComponentNm
Union nut for Fuel Pump (FP)80
Battery terminal to battery post5

Fuel level sensor -G-/Fuel level sensor 2-G169-, checking

Special tools and equipment

  1. VAG1526A Multimeter
  1. VAG1594A Adapter set

Work sequence

TT Coupe

  1. Remove rear seat bench.

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
  1. Disengage 4-pin electrical harness connector and remove (arrow).

Vehicles up to 05.02

Scheme 55

Scheme 55
Scheme 55
  1. Connect multimeter between terminal 2 and 3 for resistance measurement.
ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -G- and Fuel level sensor 2 -G169Approx. 59 ohmsApprox. 282 ohms
  1. For measured value 0 ohms there is a short circuit
  2. For measured value infinity ohms there is an open circuit.

Note. To check resistance values "tank full" or "tank empty", Fuel Pump (FP) must be removed (Refer to Fuel pump, removing and installing ) and the sensor float must be placed in the upper or lower end position. When removed, both senders are measured individually.

With fuel level sensor or fuel level sensor 2 removed, the following values will result due to the longer reach of the float arm

ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -G- (at fuel pump)Approx. 29 ohmsApprox. 147 ohms
Fuel level sensor 2 -G169Approx. 27 ohmsApprox. 140 ohms

Vehicles as of 05.02

  1. Connect multimeter between terminal 2 and 3 for resistance measurement.
ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -G- and Fuel level sensor 2 -G169Approx. 282 ohmsApprox. 59 ohms
  1. For measured value 0 ohms there is a short circuit
  2. For measured value infinity ohms there is an open circuit.

Note. To check resistance values "tank full" or "tank empty", Fuel Pump (FP) must be removed (Refer to Fuel pump, removing and installing ) and the sensor float must be placed in the upper or lower end position. When removed, both senders are measured individually.

With fuel level sensor or fuel level sensor 2 removed, the following values will result due to the longer reach of the float arm

ComponentFloat at lower end positionFloat at upper end position
Fuel level sensor -G- (at fuel pump)Approx. 147 ohmsApprox. 29 ohms
Fuel level sensor 2 -G169Approx. 140 ohmsApprox. 27 ohms

Removing

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

  1. Remove fuel pump. Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Remove secondary fuel pump. Refer to «Secondary fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__secondary-fuel-pump-removing-and-installing) .
  1. Disengage connector prongs of electrical wires -3- and -4- and disconnect.
  2. Pry off retaining straps -1- and -2- using screwdriver and remove fuel level sensor toward bottom (arrow).

Installing

Installation is the reverse of removal, noting the following

  1. Insert fuel level sensor into guides at Fuel Pump (FP) and press up until engagement.
  2. Insert connector prongs of electrical wires and check for proper engagement.
  3. Install Fuel Pump (FP). Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  4. Observe notes for connection of battery.

Fuel level sensor 2 -G169-, removing and installing

Work Sequence

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

Note. The Fuel level sensor 2 -G169- is only available as a replacement part with the secondary fuel pump assembly.

  1. Remove secondary fuel pump. Refer to «Secondary fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__secondary-fuel-pump-removing-and-installing) .

Secondary fuel pump, function

The electric Fuel Pump (FP) operates the secondary fuel pump in the left chamber of the fuel tank.

The fuel pump creates an operating stream that is pressed into the secondary fuel pump via a jet which causes acceleration. This acceleration causes the fuel in the left chamber of the fuel tank to be drawn into the right chamber of the fuel tank.

Disturbances caused by a faulty secondary fuel pump

WARNINGWhen the secondary fuel pump is faulty, the vehicle may not run if the fuel tank is about 1/4 full.

Scheme 56

Scheme 56
Scheme 56

If the secondary fuel pump -2- is not functioning, up to 15 liters of fuel -3- (up to about 1/4 of tank capacity) can remain in the left portion of the fuel tank that cannot be drawn out by the Fuel Pump (FP).

If the vehicle will not run due to lack of fuel although the tank is about 1/4 full, proceed as follows

  1. Check Fuel Pump (FP). Refer to «Fuel pump, electrical testing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

If the Fuel Pump (FP) is OK, but no fuel is being pumped

  1. Add about 5 liters of fuel to tank.
  2. Start engine.

If the engine starts now

  1. Replace secondary fuel pump. Refer to «Secondary fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__secondary-fuel-pump-removing-and-installing) .

Secondary fuel pump, removing and installing

Special tools and equipment

  1. Ring nut spanner 3217
  1. Observe safety precautions. Refer to «Safety rules when working on fuel supply system»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Observe rules for cleanliness. Refer to «Rules of cleanliness»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__rules-of-cleanliness) .
  1. When removing the secondary fuel pump, the fuel tank should be less than 1/3 full. If necessary, empty the fuel tank. Refer to «Fuel tank, emptying»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  1. Remove Fuel Pump (FP). Refer to «Fuel pump, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

TT Roadster

  1. Remove rear panel side trim.

Continued for all vehicles

  1. Unscrew cover -1- at right (arrows).
WARNINGFuel tank must be less than 1/3 full when removing fuel pump.

Scheme 57

Scheme 57
Scheme 57
  1. Use ring nut spanner 3217 to remove union nut.
  1. Pull connecting flange and secondary fuel pump (with fuel lines connected) out of fuel tank opening.

Installation is the reverse of removal, noting the following

  1. Insert fuel lines of secondary fuel pump through opening for secondary fuel pump and through to right chamber of fuel tank.

Note. Insert new, dry seal for connection flange into opening of fuel container. When inserting Fuel Pump (FP) into fuel tank, be sure not to bend floating arm of fuel level sensor.

Scheme 58

Scheme 58
Scheme 58
  1. Press connecting flange into opening, note installation position
  1. Marking on connecting flange must align with marking on fuel tank (arrows).
  1. Use ring nut spanner 3217 to tighten union nut (80 Nm).
  2. Install Fuel Pump (FP). Refer to «Installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) , (Observe notes for connecting battery.)

Tightening torque

ComponentNm
Union nut for secondary fuel pump80

Scheme 59

Scheme 59: Component overview
Scheme 59: Component overview

1 - Cover

  1. For EVAP canister

2 - Vent line

  1. To Evaporative Emission (EVAP) canister purge regulator valve -N80

3 - Vent line

  1. From gravity valve and pressure retention valve at fuel tank

4 - Sealing piece

5 - EVAP canister

  1. Installation location: below spare tire compartment
  2. Removing and installing. Refer to «Evaporative Emission (EVAP) canister, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__evaporative-emission-evap-canister-removing-and)

6 - Vacuum line

  1. To Leak Detection Pump (LDP) -V144

7 - Bracket

  1. For air filter

8 - Air filter

9 - O-Rings

  1. Always replace

10 - Evaporative Emission (EVAP) canister purge solenoid valve -N115

  1. Checking. Refer to «Evaporative Emission (EVAP) canister purge solenoid valve -N115-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

11 - Retaining ring

12 - 5 Nm

13 - Bracket

  1. For Evaporative Emission (EVAP) canister purge solenoid valve -N115

14 - Electrical 2-pin harness connector

  1. Black

15 - Bushing

16 - Grommet

17 - Pin bolt, 16 Nm

18 - Grommet

19 - Washer

20 - Cap nut, 9 Nm

Scheme 60

Scheme 60: Evaporative Emission (EVAP) canister purge solenoid valve -N115-, checking
Scheme 60: Evaporative Emission (EVAP) canister purge solenoid valve -N115-, checking

Special tools and equipment

  1. VAG1526A Multimeter
  2. VAG1527B Voltage tester
  3. VAG1594A adapter set
  4. VAG1598/31 Test bos
  1. VAS5051 Vehicle diagnosis, testing and information system with VAG5051/1 Adapter

Checking function

  1. Parking brake engaged.
  2. Vehicles with manual transmission: shift lever in neutral.
  3. Vehicles with automatic transmission: selector lever in P or N.

Note. Checking seal (performing leak testing). Refer to Evaporative Emission (EVAP) system, diagnostic leak test. For leaking Evaporative Emission (EVAP) canister purge solenoid valve -N115-, replace O-rings. (Scheme 62) Ignition on.

Scheme 61

Scheme 61
Scheme 61
  1. VAS 5051 tester connected and -"01 Engine electrical"- selected.

Scheme 62

Scheme 62
Scheme 62

Display on VAS 5051

  1. In selection -1-, click on diagnostic function "03 - Diagnosis"
  2. Click on delta button until Evaporative Emission (EVAP) canister purge solenoid valve -N115- is activated
  1. Evaporative Emission (EVAP) canister purge solenoid valve -N115- will be activated for about 1 minute (clicks).

Note. The noise of the solenoid valve is audible in the area of the rear axle

  1. End the function "03 - Output check diagnosis" by clicking <-- button.
  2. Select "06 - End Process".
  3. Turn off ignition.

If the Evaporative Emission (EVAP) canister purge solenoid valve -N115- is not activated (no noise audible)

  1. Check internal resistance, Evaporative Emission (EVAP) canister purge solenoid valve -N115-. Refer to «Checking internal resistance»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__checking-internal-resistance) .

Checking internal resistance

Vehicles with Front Wheel Drive (FWD)

Scheme 63

Scheme 63: Checking internal resistance
Scheme 63: Checking internal resistance
  1. Remove EVAP canister cover, below, at spare tire compartment (arrows).

Vehicles with All Wheel Drive (AWD)

Scheme 64

Scheme 64
Scheme 64
  1. Disconnect exhaust system at clamping sleeve (arrows).
  2. Remove right rear bracket for exhaust system.
  3. Disengage rear portion of exhaust system at brackets.

Note. The exhaust system release element must not be bent more than 10° , otherwise it could be damaged.

Scheme 65

Scheme 65
Scheme 65
  1. Remove rear heat shield and bracket for exhaust system (arrows).

Scheme 66

Scheme 66
Scheme 66
  1. Remove rear nut (arrow) of cover for EVAP canister.
  2. Fold cover for EVAP canister down at rear edge.

Continued for all vehicles

Scheme 67

Scheme 67
Scheme 67
  1. Disconnect electrical harness connector (arrow).

Note. Illustration depicts a vehicle with Front Wheel Drive (FWD).

  1. Connect multimeter at valve for resistance measurement.
  1. Specified value: 22-26 ohms

If specified value is not obtained

  1. Replace Evaporative Emission (EVAP) canister purge regulator valve -N115-.

If specified value is obtained

  1. Check voltage supply. Refer to «Checking voltage supply»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__checking-voltage-supply) .

Checking voltage supply

Note. Voltage supply test of Evaporative Emission (EVAP) canister purge solenoid valve -N115- is performed via the Fuel Pump (FP) relay.

Requirements

  1. Parking brake engaged.
  2. Vehicles with manual transmission: shift lever in neutral.
  3. Vehicles with automatic transmission: selector lever in P or N`.
  4. Fuse for Evaporative Emission (EVAP) canister purge solenoid valve -N115- OK
  1. Disconnect connector at Evaporative Emission (EVAP) canister purge solenoid valve -N115-.

Scheme 68

Scheme 68
Scheme 68
  1. Connect VAG1527B voltage tester as follows
Electrical harness connector terminal numberMeasure to
1Ground (GND)
  1. Operate starter briefly (OK for engine to start).
  1. LED must light

If LED does not light

  1. Check electrical wire connection from terminal 1 via fuse to Fuel Pump (FP) relay for open circuit.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

  1. Repair open circuit if necessary.

If wire connection is OK

  1. Check Fuel Pump (FP) relay.

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

If LED lights

  1. Check activation. Refer to «Checking activation»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__checking-activation) .

Checking activation

Requirement

  1. Voltage supply OK
  1. Connect VAG1527B voltage tester to connector terminals 1 (B+) and 2.
Electrical harness connector terminal numberMeasure to
2Battery +
  1. Initiate output Diagnostic Test Mode (DTM) and activate evaporative emission (EVAP) canister purge solenoid valve -N115- as described under «Checking function»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__checking-function) .
  1. LED must blink

If LED does not blink

  1. Switch ignition off.
  2. Remove wiper arms.
  3. Remove plenum chamber cover and set aside on windshield side.
  4. Disengage locking tabs and remove control module connector.

Scheme 69

Scheme 69
Scheme 69
  1. Connect VAG1598/31 test box to connector of wiring harness. Ground (GND) clip (arrow) at test box must be clipped to battery negative. Engine Control Module (ECM) must not be attached.

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Check following wire connection for open circuit and short circuit to Ground (GND) and B+
Electrical Harness connector TerminalVAG1598/31 test box socket
2116 (4-cyl.)
2116 (6-cyl.)
  1. Repair open circuit or short circuit if necessary.

If wire connection is OK, but the Evaporative Emission (EVAP) Canister Purge Solenoid Valve does not function

  1. Replace Engine Control Module (ECM).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Observe safety precautions after re-connecting Engine Control Module (ECM).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

Evaporative Emission (EVAP) canister, removing and installing

Note. Checking for proper seal (leak testing). Refer to Evaporative Emission (EVAP) system, diagnostic leak test .

Removing

Observe safety precautions. Refer to Safety rules when working on fuel supply system .

Observe rules for cleanliness. Refer to Rules of cleanliness .

Vehicles with Front Wheel Drive (FWD)

  1. Remove EVAP canister cover at bottom of spare tire well (arrows).

Vehicles with All Wheel Drive (AWD)

  1. Disconnect exhaust system at clamping sleeve (arrows).
  2. Remove right rear bracket for exhaust system.
  3. Disengage rear portion of exhaust system at brackets.

Note. The exhaust system release element must not be bent more than 10° , otherwise it could be damaged.

  1. Remove rear heat shield and bracket for exhaust system (arrows).

Scheme 70

Scheme 70
Scheme 70
  1. Remove rear bolts -3- of subframe at left and right.
WARNINGSubframe will sink about 100 mm when bolts are loosened.

Note. To avoid the need for an alignment, subframe must only be released (i.e. lowered) on rear side.

  1. Remove bolts -1- and -2- of stabilizer at left and right.
  2. Swing stabilizer down.

Scheme 71

Scheme 71
Scheme 71
  1. Remove cover of EVAP canister at bottom of spare tire well (arrows).

Continued for all vehicles

Scheme 72

Scheme 72
Scheme 72
  1. Remove vacuum line -1- to Leak Detection Pump (LDP) -V144- by pressing on release button.
  2. Disconnect electrical harness connector for Evaporative Emission (EVAP) canister purge solenoid valve -N115- -2-.

Scheme 73

Scheme 73
Scheme 73
  1. Disconnect hose connections -1- and -2- at vent lines.
  2. Unscrew pin bolts (arrows) and remove EVAP canister.

Installing

Installation is the reverse of removal, noting the following

Note. Secure all hose connections using hose clamps appropriate for the model type

Vehicles with All Wheel Drive (AWD)

  1. Secure subframe using new bolts
  1. Secure stabilizer
  1. Adjust exhaust system to be tension free

Refer to

  1. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-amu-bea) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): AMU, BEA
  2. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-mechanical-engine-codes-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO ENGINE MECHANICAL, ENGINE CODE(S): ATC, AWP
  3. «26 EXHAUST SYSTEM, EMISSION CONTROLS»(ref-276269-S01656351712008010300000) for 3.2 LITER V6 4V ENGINE MECHANICAL, ENGINE CODE(S): BHE

Tightening torques

ComponentNm
EVAP canister at chassis16
Cover at spare tire well9

Scheme 74

Scheme 74: Evaporative Emission (EVAP) canister purge regulator valve -N80-, component overview
Scheme 74: Evaporative Emission (EVAP) canister purge regulator valve -N80-, component overview

Note. Arrows on the hose and/or pipe connections must line up across from each other.

1 - Grommet

2 - Bushing

3 - 8 Nm

4 - Vacuum reservoir

5 - Check valve

  1. Inserted in vacuum reservoir

6 - Bracket

  1. For Evaporative Emission (EVAP) canister purge regulator valve -N80

7 - Test connection

8 - Evaporative Emission (EVAP) canister purge regulator valve -N80

  1. Checking function and activation

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

9 - From EVAP canister

10 - 2-pin harness connector

  1. For Evaporative Emission (EVAP) canister purge regulator valve -N80

11 - Check valve

  1. Only vehicles with turbocharger
  2. Installed position (light/dark half): arrow points in direction of flow see scheme 170

12 - To intake tubes at turbocharger

  1. Only vehicles with turbocharger

13 - Check valve

  1. Only vehicles with turbocharger
  2. Installed position (light/dark half): arrow points in direction of flow see scheme 170

14 - To intake manifold

15 - Grommet

16 - To EVAP canister

17 - Grommet

18 - Bracket

  1. For vacuum reservoir

19 - 8 Nm

Scheme 75

Scheme 75: Evaporative Emission (EVAP) canister system with Leak Detection Pump (LDP), hose diagram
Scheme 75: Evaporative Emission (EVAP) canister system with Leak Detection Pump (LDP), hose diagram

1 - Evaporative Emission (EVAP) canister purge regulator valve -N80

  1. Installation location: front right in engine compartment
  2. Component overview. Refer to «Evaporative Emission (EVAP) canister purge regulator valve -N80-, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)
  3. Checking

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

2 - Air filter

  1. For Leak Detection Pump (LDP) -V144

3 - Leak Detection Pump (LDP) -V144

  1. Installation location: in front right wheel housing under wheel housing liner
  2. Checking. Refer to «Leak Detection Pump (LDP) -V144-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-checking)
  3. Removing and installing. Refer to «Leak Detection Pump (LDP) -V144-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-removing)

4 - Test connection

5 - Vent line

  1. From gravity valve and pressure retention valve at fuel tank

6 - EVAP canister

  1. Installation location: bottom of spare tire well
  2. Removing and installing. Refer to «Evaporative Emission (EVAP) canister, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__evaporative-emission-evap-canister-removing-and)

7 - Air filter

  1. For Evaporative Emission (EVAP) canister purge solenoid valve -N115

8 - Evaporative Emission (EVAP) canister purge solenoid valve -N115

  1. Checking. Refer to «Evaporative Emission (EVAP) canister purge solenoid valve -N115-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

9 - Check valve

  1. Only vehicles with turbocharger
  2. Installed position (light/dark half): arrow points in direction of flow see scheme 171

10 - Turbocharger

  1. Only vehicles with turbocharger

11 - Throttle valve control module -J338

12 - Check valve

  1. Only vehicles with turbocharger
  2. Installed position (light/dark half): arrow points in direction of flow see scheme 171

13 - Check valve

  1. Inserted in vacuum reservoir

14 - Vacuum reservoir

  1. For Leak Detection Pump (LDP) -V144
  2. Component overview. Refer to «Evaporative Emission (EVAP) canister purge regulator valve -N80-, component overview»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system)

Evaporative Emissions (EVAP) system diagnostic leak test, function

The EVAP system diagnostic leak test recognizes leaks in the entire fuel system including the fuel tank, Evaporative Emission (EVAP) canister, EVAP canister purge regulator valve -N80- and the EVAP canister purge solenoid valve -N115-.

On the mechanical side, the leak detection system consists primarily of a vacuum activated diaphragm pump with a reed contact on an activating rod at the pump diaphragm. The pump is supplied its vacuum via the engine intake.

  1. When the diagnostic leak test is initiated, the Leak Detection Pump (LDP) increases pressure in the fuel system to 20-30 mbar.
  2. Once the specified pressure is reached, the pump membrane remains expanded so that the reed contact at the operating rod remains in the "open" position.
  3. If pressure falls (indicating a leak), the diaphragm moves and the reed contact closes.
  4. First the diagnostic will test whether the reed contact closes within 10 seconds. If it does not, the fuel system is sealed.
  1. If the reed contact closes within 10 seconds, however, the system has a leak. If this is the case, the membrane pump will pump four additional strokes. The Engine Control Module (ECM) measures the time between these four strokes and closure of the reed contact. Based on this measurement, the ECM recognizes whether the leak is larger than 1 mm in diameter and can distinguish a "small leak" from a "large leak."

Leak testing is initiated shortly following every engine start. If a malfunction is recognized, a DTC entry follows. The Malfunction Indicator Lamp (MIL) in the instrument cluster will light if the malfunction is recognized for two subsequent starts. Leak detection can also be activated using the VAS5051 tester. Refer to Evaporative Emission (EVAP) system, diagnostic leak test .

Automatic diagnostic leak test

With engine running, the control module performs a diagnostic leak test in certain intervals.

Whether an automatic diagnostic leak test is just being performed can be determined with a connected VAS 5051 tester in measuring value block 071, Guided fault finding in the VAS 5051.. Refer to Evaporative Emission (EVAP) system, diagnostic leak test .

Evaporative Emission (EVAP) system, diagnostic leak test

Special tools and equipment

Scheme 76

Scheme 76: Evaporative Emission (EVAP) system, diagnostic leak test
Scheme 76: Evaporative Emission (EVAP) system, diagnostic leak test
  1. VAS 5051
  1. Observe safety precautions. Refer to «Safety rules when working on fuel supply system»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  2. Observe rules for cleanliness. Refer to «Rules of cleanliness»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__rules-of-cleanliness) .

Note. All hose connections are secured with clips. Always replace seals and gaskets.

Requirements

  1. Parking brake engaged.
  2. Vehicles with manual transmission: shift lever in neutral.
  3. Vehicles with automatic transmission: selector lever in P or N.
  4. Engine is running at idle
  1. Electrical consumers switched off (coolant fan must NOT run during test)
  2. A/C switched off
  1. VAS 5051 tester connected and -"01 Engine electrical" selected.
  2. No DTCs in DTC memory
  3. Intake Air Temperature (IAT) less than 90° C. Refer to display group 004, display field 4
  4. Coolant Temperature less than 95° C. Refer to display group 004, display field 3
  1. Throttle valve angle less than 10° % display group 003, display field 3

Work sequence

Display on VAS 5051

  1. In selection -1-, click on diagnostic function "04 - Basic setting".

Scheme 77

Scheme 77
Scheme 77

Display on VAS 5051

1 - Enter display group

  1. Select function "071" in button field -2- for "display group number 071" and press Q button to confirm input.

Scheme 78

Scheme 78
Scheme 78

Display on VAS 5051

  1. Check indication in display field 1.
  1. Specification: "Reed closed"

Note. If "Reed cl" (closed) is displayed, continue test. If display indicates "Reed open": briefly open and close fuel filler cap to release pressure from fuel tank. This will close the reed contact.

  1. Activate basic setting by pressing button A.
  2. Check indication in display field 4.
  1. Specification: "Test ON"

The system test lasts several minutes.

  1. Check indication in display field 4.
  1. Specification: "System OK"

System is sealed, test is terminated.

  1. End function "04 - Basic setting" by pressing <-- button.

DTC display

If a DTC is recognized during the system test, the DTC evaluation follows.

On VAS 5051 display in display field -4

  1. In case of malfunction: System not OK
  1. Check diagnosis evaluation in display field -2-.
  1. "Small leak" or "large leak"
  1. End function "04 - Basic setting" by pressing <-- button.

If the system recognizes a small or large leak

  1. Checking fuel supply and ventilation systems for leaks. Refer to «Checking fuel supply and ventilation systems for leaks»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__checking-fuel-supply-and-ventilation-systems) .
  2. After that, repeat leak test.

Checking fuel supply and ventilation systems for leaks

Note. The following describes areas in the fuel supply and ventilation systems that should be checked for possible leaks. After making necessary repairs, perform leak test again to ensure that all leaks were successfully repaired.

  1. Switch ignition off.
  2. Check whether fuel filler cap was completely closed for test.
  3. Check seal of fuel filler cap for damage. Replace if necessary.

TT Coupe

  1. Remove rear seat bench.

Vehicles with Front Wheel Drive (FWD)

TT Roadster

  1. Remove rear panel side trim.
  1. Unscrew cover -1- at right (arrows).

Vehicles with All Wheel Drive (AWD)

TT Roadster

  1. Remove rear panel side trim.
  1. Unscrew cover -1- at right (arrows).

Continued for all vehicles

  1. Check whether seals under connection flanges are OK and union nuts are properly tightened. Also check fuel line connections.

Note. Observe installation notes for connector flanges. Refer to Installing , Installing , or Removing .

  1. Visually check all wires and hose connections of fuel supply system and replace loose lines, e.g.
  1. Line from EVAP canister to Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80 (in engine compartment)
  2. Lines from EVAP canister to Leak Detection Pump (under front right wheel housing liner)
  3. Line from fuel tank to Evaporative Emission (EVAP) canister (under cover for EVAP canister)
  4. Lines from EVAP system (under right wheel housing liner)
  1. Fuel lines to engine

Note. Leaks at lines and components of fuel supply system can sometimes be located using a non-flammable, environmentally sound leak detection spray. For this, initiate leak testing several times in sequence to build pressure in the system. Leaks can be detected via bubbles forming at the leak.

  1. Visually check components of fuel supply system and EVAP system.
  1. Fuel tank
  2. EVAP canister
  3. Leak Detection Pump (LDP) -V144
  4. Evaporative Emission (EVAP) canister purge regulator valve -N80
  1. Evaporative Emission (EVAP) canister purge solenoid valve -N115

Note. Because of the shape or function of these components it is not always possible to find leaks by applying spray. It may be necessary to clamp off the relevant component using 3094 hose clamps and initiate the leak detection diagnostic. If the leak is no longer detected, the component that was clamped off is faulty. If the clamp is placed directly on the diagnostic pump and a leak is still detected, then the diagnostic pump itself is leaking. Checking Evaporative Emission (EVAP) canister purge regulator valve -N80

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. For leaking Evaporative Emission (EVAP) canister purge solenoid valve -N115-, replace O-rings. (Scheme 62)

Work sequence

  1. Ignition on
  1. VAS 5051 tester connected and "01 Engine electrical" selected.

Display on VAS 5051

  1. Click on diagnostic function -1- "03 Output check diagnosis"
  2. Click delta button until leak detection pump begins functioning.

Scheme 79

Scheme 79: Leak Detection Pump (LDP) -V144-, component overview
Scheme 79: Leak Detection Pump (LDP) -V144-, component overview

1 - Bracket

  1. For air filter

2 - Air filter

  1. For Leak Detection Pump (LDP) -V144

3 - Hose

4 - Leak Detection Pump (LDP) -V144

  1. Installation location: in front right wheel housing under wheel housing liner
  2. Checking. Refer to «Leak Detection Pump (LDP) -V144-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-checking)
  3. Removing and installing. Refer to «Leak Detection Pump (LDP) -V144-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-removing)

5 - 3-pin harness connector

6 - Vacuum line

  1. To EVAP canister

7 - Set pin

8 - Bracket

9 - Grommet

10 - Grommet

11 - Bushing

12 - 8 Nm

13 - Vacuum line

  1. To vacuum reservoir, at right in engine compartment

14 - 8 Nm

15 - Bushing

16 - Grommet

17 - 5 Nm

Leak Detection Pump (LDP) -V144-, checking

Special tools and equipment

  1. VAG1526A Multimeter
  2. VAG1527B Voltage tester
  3. VAG1594A Adapter set
  4. VAG1598/31 Test box
  1. VAS5051 Vehicle diagnosis, testing and information system

Requirements

  1. Ignition on
  1. VAS 5051 tester connected and "01 Engine electrical" selected

Display on VAS 5051

  1. Click on diagnostic function -1- "03 Output check diagnosis"
  2. Click delta button until leak detection pump is activated.
  1. Leak Detection Pump (LDP) -V144- will be activated for approximately 1 minute.

Note. Operating noise of Leak Detection Pump (LDP) is audible at front right wheel housing.

  1. Click <-- button to end the function "03-Output check diagnosis"
  2. Select 06 End sequence.
  3. Switch ignition off.

If LDP is not activated (no audible operating noise)

  1. Remove Leak Detection Pump (LDP) -V144-(Refer to «Leak Detection Pump (LDP) -V144-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-removing) ), and disconnect harness connectors.

Checking internal resistance

Scheme 80

Scheme 80
Scheme 80
  1. Connect multimeter for resistance measurement as follows.
Leak Detection Pump (LDP) -V144- terminalsSpecified value
1 + 3640-720 ohms
2 + 315-17 ohms

If specified values are not obtained

  1. Replace Leak Detection Pump (LDP) -V144-. Refer to «Leak Detection Pump (LDP) -V144-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-removing) .

If specified values are obtained

  1. Check voltage supply at harness connector of Leak Detection Pump (LDP). Refer to «Checking voltage supply»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .

Note. Voltage supply for the Leak Detection Pump (LDP) runs via the Fuel Pump (FP) relay.

Requirement

  1. Fuse for Leak Detection Pump (LDP) OK
  1. Disconnect connector at Leak Detection Pump (LDP).

Scheme 81

Scheme 81
Scheme 81
  1. Connect VAG1527B voltage tester as follows
Electrical harness connector terminalMeasure to
3Engine Ground (GND)
  1. Operate starter briefly.
  1. LED must light

If LED does not light

  1. Check electrical wire connection from terminal 3 via fuse to Fuel Pump (FP) relay for open circuit.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

  1. Repair open circuit if necessary.

Checking output wire

  1. Connect VAG1527B voltage tester as follows
Electrical harness connector terminalMeasure to
2Battery +
  1. Initiate output Diagnostic Test Mode. Refer to «Checking function»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system) .
  1. LED must blink.

If LED does not blink

  1. Click <-- button to end function "03 Output check diagnosis"
  2. Select "06 End sequence"
  3. Switch ignition off.
  1. Connect VAG1598/31 test box to connector of wiring harness. Engine Control Module (ECM) must not be attached. Ground (GND) clip (arrow) at test box must be clipped to battery negative terminal (arrow).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Check following wire connection for open circuit and short circuit to Ground (GND) and B+
Electrical harness connector terminalVAG1598/31 test box socket
225
  1. Repair open circuit or short circuit if necessary.

If no malfunctions are found, but Leak Detection Pump (LDP) does not function during output Diagnostic Test Mode (DTM)

  1. Replace Leak Detection Pump (LDP) -V144-. Refer to «Leak Detection Pump (LDP) -V144-, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#fuel-supply-system__leak-detection-pump-ldp-v144-removing) .
  2. Observe safety precautions after re-connecting Engine Control Module (ECM).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE

Checking input wire

  1. Switch ignition off.
  1. Connect VAG1598/31 test box to connector of wiring harness. Engine Control Module (ECM) must not be attached. Ground (GND) clip (arrow) at test box must be clipped to battery negative terminal (arrow).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Check following wire connection for open circuit and short circuit to Ground (GND) and B+
Electrical harness connector terminalVAG1598/31 test box socket
180
  1. Repair open circuit or short circuit if necessary.
  2. Observe safety precautions after re-connecting Engine Control Module (ECM).

Refer to

  1. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «24 MULTIPORT FUEL INJECTION (MFI)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276272-S33271097972008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276273-S13509179772008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA
  5. «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) for 3.2 LITER V6 4V FUEL INJECTION & IGNITION, ENGINE CODE(S): BHE
  1. Generate readiness code.

Refer to

  1. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-amu) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
  2. «01 ON BOARD DIAGNOSTIC (OBD)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
  3. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276272-S12227258552008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
  4. «01 ON BOARD DIAGNOSTIC (OBD)»(ref-276273-S13756956692008010300000) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

Leak Detection Pump (LDP) -V144-, removing and installing

Removing

  1. Remove right front wheel.
  2. Remove cover for vacuum lines.
  3. Remove right rear wheel housing liner.

Scheme 82

Scheme 82
Scheme 82
  1. Disconnect hose connections -2- and -3- (connector coupling at metal sheet, engine side).
  2. Remove bolts (arrows).
  3. Remove LDP, disengage harness connector -1- with ignition off and disconnect.

Installing

Installation is the reverse of removal, noting the following

Note. Secure all hose connections using hose clamps appropriate for the model type.

Tightening torque

ComponentNm
Bracket for leak detection pump at wheel housing8

Scheme 83

Scheme 83: Accelerator pedal cable, servicing
Scheme 83: Accelerator pedal cable, servicing

1 - Rubber pedal cover

2 - 10 Nm

3 - 6-pin harness connector

4 - Accelerator pedal module

  1. With Throttle Position (TP) sensor -G79- and Accelerator pedal position sensor 2 -G185

Removing and installing accelerator pedal module with Throttle Position (TP) sensor -G79- and Accelerator pedal position sensor 2 -G185

  1. Remove driver-side storage compartment.

Scheme 84

Scheme 84
Scheme 84
  1. Disconnect 6-pin harness connector -2-.
  2. Remove nuts -1- and -3-.
  3. Remove accelerator pedal module.

Installation is the reverse of removal.

Tightening torque

ComponentNm
Accelerator pedal module at pedal mount10

Vehicles with automatic transmissions or Direct Shift automatic transmission

If Accelerator pedal position sensor 2 -G185- or Engine Control Module (ECM) is replaced, kick-down function must be adapted on vehicles with automatic transmission or Direct Shift automatic transmission.

Conditions

  1. Connect VAS 5051 scan tool and select vehicle system "01 -Engine electrical" in selection.
  2. No DTCs recorded in DTC memory.
  3. Engine stopped, ignition switched on.
  1. Enter "063" for "display group number 063".

Display on VAS 5051

  1. Monitor display fields -3- and -4-.

Indication on display: "Activate Kick-down"

  1. Depress accelerator pedal completely, past kick-down point, and hold down.

Indicated on display: "Kick-down ADP running"

  1. Check desired values in display fields -3- and -4-.

Indicated on display: "Kick-down ADP OK"

Note. If "Kick-down ERROR" is displayed, check DTC memory "ERROR" may be displayed, if accelerator pedal is not pressed immediately when instructed by tester, or if accelerator pedal was released while adaptation was already running but process was not yet complete. In both cases exit "04 - basic setting" mode by clicking the <-- button and performing adaptation again.

  1. End "04 - Basic Setting" by clicking <-- button.
  2. Select diagnostic function "06 - End Sequence".
  3. Switch ignition off and disconnect diagnostic connection.

See also:
• 24 MULTIPORT FUEL INJECTION (MFI)
• 24 MULTIPORT FUEL INJECTION (MFI)
• 72 - SEAT - FRAMES
• 42 REAR SUSPENSION
• 26 EXHAUST SYSTEM, EMISSION CONTROLS
• 26 EXHAUST SYSTEM, EMISSION CONTROLS
• 26 - EXHAUST SYSTEM, EMISSION CONTROLS
• 66 EXTERIOR EQUIPMENT
• 39 FINAL DRIVE, DIFFERENTIAL
• Safety rules when working on fuel supply system
• Rules of cleanliness
• Fuel tank with attachments, removing and installing
• Removing, installing, and checking gravity valve
• Fuel filler tube, component overview
• A - Procedure for fuel tank more than 3/4 full
• B - Procedure for fuel tank less than 3/4 full
• Fuel pump, removing and installing
• Fuel pump, electrical testing
• Fuel level sensor -G-, checking
• Fuel level sensor -G-, removing and installing
• Fuel tank, emptying
• Fuel level sensor -G-/Fuel level sensor 2-G169-, checking
• Secondary fuel pump, removing and installing
• Evaporative Emission (EVAP) canister, removing and installing
• Evaporative Emission (EVAP) system, diagnostic leak test
• Checking internal resistance
• Checking voltage supply
• Checking activation
• Checking function
• Leak Detection Pump (LDP) -V144-, checking
• Leak Detection Pump (LDP) -V144-, removing and installing
• Checking fuel supply and ventilation systems for leaks

More articles — Engine