Audi A3 2004 User Manual

Service Training

Audi A3 Sportback

Self-Study Programme 332

Audi A3 Sportback

Audi is defining a new segment in the premium compact class. The A3 Sportback is characterised by the sporting elegance of a coupé and the versatility of a 5-door.

The Audi Sportback is deliberately going its own, new way in the compact class. It offers the emphatically sporty qualities and the athletic styling of the three-door version with which it shares its drive train, dynamic suspension and wheelbase. In addition to two rear doors, it offers even more space and variability thanks to its rear end which is a total of 68 millimetres longer than on its threedoor counterpart.

The A3 Sportback is immediately recognisable at first glance in the rear-view mirror by its striking single-frame radiator grille, the distinctive tapering of the sides and the dynamic shape of the clearglass headlights.

The silhouette of the A3 Sportback when viewed from the side becomes flatter towards the rear of the car in typical coupé fashion and combines with the gently rearward sloping roof line and the restyled rear end to give the car its dynamic overall proportions.

Excellence in design & performance

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Contents

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

Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Running gear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Convenience electronics . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Infotainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

The S elf -S tud y Pro gramm e conveys basic principles with regard to the design and function of new models, new automotive components or new technologies.

The Self-Study Programme is not a Repair Manual! All values given are intended as a guideline only, and refer to the software version valid at the time of publication of the SSP.

For maintenance and repair work, always refer to the current technical literature.

NoteReference

Introduction

Overview

Dimensions of the A3 Sportback.

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Body

The body of the Audi A3 Sportback has a highly rigid and crash-optimised occupant cell.

Special attention was given to the following aspects:

● the body rigidity,

● the steering column rigidity,

● local rigidity in highly stressed areas,

● interior acoustics and driving comfort,

● the crash optimised body structure and

● the hybrid construction of the front end.

Front view of the body-in-white

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Rear view of the body-in-white

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By using state-of-the-art calculation and simulation methods, new materials and joining techniques, and by optimising the joining sequence during the bodyshell assembly process, it was possible to increase body rigidity by 20% compared to the predecessor model and enhance the crash performance of the body structure.

Body

Materials

Bodyshell

Ultra-high-strength and higher-strength sheet metal are used in areas which are subjected to high mechanical stresses during a crash.

Welded tailored blanks and deep-drawn sheet metal are used in other areas.

Ultra-high-strength sheet metal higher-strength sheet metal

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Body

Materials

Doors, sills and floorpan

Welded tailored blanks and tailored blanks with flexible rolled wall thickness are used in the front floorpan assembly and door areas. The result is a distribution of material which provides optimum stress absorption.

The sills are reinforced using rolled profiles. Rolled profiles have a high strength-to-weight ratio.

Ta ilored blanks

Rolled profile

Tai lo re d b l ank s

Rolled profile

Ta ilored blanks

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Joining technique

Various joining techniques are applied to interconnect the individual body elements.

Spot welding joining

Crash-relevant and rigidity-defining joints are spot-weld bonded using a high-strength structural adhesive. The overall length of the bonded seams is approx. 26 m.

Laser welding

Laser welding is used in areas which are not easily accessible. The total length of the laser welded joints is approx. 25 m.

Laser soldering

Laser-solder joining is used to achieve a better design and higher rigidity in the area of the invisible joint and boot lid. The total length of the laser-soldered joints is approx. 3.3 m

Plasma soldering

To e n s u re the high rigidity and good design of the water channel, materials are joined by plasma soldering. The overall length of the plasma-soldered joints is approx. 1.1 m.

Laser-welded joints Laser-soldered joints Plasma-soldered joints

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Body

Roof rail

Description

The Audi A3 Sportback has a roof rail whose new style design accentuates the car's coupe like roofline. It is made from aluminium and is available in two finishes: –high-gloss anodised or –black powder-coated

Mounting bolts

Mounting

The roof rail is mounted to the roof side member using four bolts.

Rivet nut

Roof side member exterior

Bolt

Roof

To le ra n ce compensation element

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Nut-and-washer assembly

Head airbag

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Open Sky roof

Description

The optional Open Sky roof creates a more pleasant interior climate. It lets more light into the car and allows the occupants a view of the sky above. The front glass segment can be opened completely and slid back. Two s e p a rate sun blinds protect against the glare of the sun and can also be used when the glass roof is open.

Open Sky roof open

Function

Opening is powered by an electric motor. When opening, the glass roof moves upwards and outwards. Operation is by pushbutton. The glass roof halts in the position in which the pushbutton is released.

Open Sky roof closed

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Occupant protection

Safety system

Like the system in the Audi A3 3-door, the safety system in the Audi A3 Sportback is built to the highest standards. The long list of safety requirements includes full compliance with legislation currently in force, as well as consumer tests with the aim of achieving class-leading car safety ratings for the new Audi A3 Sportback. Audi's internal requirements often present the development team with additional challenges. Special emphasis was placed on a high level of occupant protection in accidents and on compatibility. Audi's "safety first" approach to vehicle design complements the information derived from scientific analysis of actual accidents and their impacts. To this end, the Audi Accident Research Unit ( AARU) analyses the data from accidents involving recent Audi vehicles. The task of the research team is to analyse and reconstruct accidents, and to identify areas where there is potential for improvement. In addition to this, the AARU evaluates the information stored in the respective accident databases.

The differences to the Audi A3 `04 are highlighted on the following pages.

The safety system in the Audi A3 Sportback consists of the following components:

–Airbag control unit –Dual-stage driver and front passenger airbags –Front side airbags –Sideguards (head airbags) –Side impact detection sensors on the C-pillar –Side impact detection sensors in the front doors –Crash sensors for differentiated head-on collision detection, otherwise known as "upfront" sensors –Front belt tensioners –Battery disconnector, only for models with battery in luggage compartment –Switches in the front seat-belt buckles –Seat occupied sensor, front passenger side

The vehicle can also be equipped with rear side airbags and a keyswitch with associated warning lamp for deactivating the front passenger airbag.

The a ctive head restraints in the front seats round off the safety system in the Audi A3 Sportback.

Note

Follow the safety instructions in the repair manual before performing any work on the airbag system!

Legend

E224 Front passenger side airbag deactivation key switch E24 Driver side belt switch E25 Front passenger side belt switch

G128 Seat occupied sensor, front passenger side G179 Side airbag crash sensor, driver side (front door) G180 Side airbag crash sensor, front passenger side (front door) G256 Rear side airbag crash sensor, driver side (C-pillar) G257 Rear side airbag crash sensor, front passenger driver side (C-pillar) G283 Driver side front airbag crash sensor (frontend left) G284 Front passenger side front airbag crash sensor (frontend right)

J220 Engine control unit J234 Airbag control unit J285 Control unit with display in dash panel insert J393 Convenience system central control unit J533 Data bus diagnostic interface (Gateway)

K19 Seat belt warning system warning lamp K75 Airbag warning lamp K145 Front passenger side airbag deactivated warning lamp

(PASSENGER AIRBAG OFF) N95 Airbag igniter, driver side N250 Driver side airbag igniter -2N131 Front passenger side airbag igniter 1 N132 Front passenger side airbag igniter 2

N153 Driver seat belt tensioner igniter -1N154 Front passenger seat belt tensioner igniter -1N199 Side airbag igniter, driver side N200 Side airbag igniter, f ro n t pa ssenger side N251 Driver side curtain airbag igniter N252 Front passenger side curtain airbag igniter N253 Battery isolation igniter

T16 16-pin connector, diagnosis connection

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Occupant protection

Airbag control unit J234

The a irbag control unit's hardware and electronics have been modified compared to the control unit in the Audi A3 3-door such that they are also capable of activating the dual-stage front airbags. The airbag control unit has also been modified in such a way that no mechanical safing sensor is required.

The a irbag control unit is integrated in the drive train CAN bus.

The a irbag electronics basically have the following tasks:

–collision detection (front, side, rear) –defined deployment of the airbags or front

airbag stages, belt tensioners and battery

disconnector –activation of the belt-on indicator –evaluation of all input information –continuous monitoring of the entire airbag

system –capacitor-based independent power supply for

a defined period of time

(approx. 150 ms) –fault display by failure warning lamp –storage of fault/ and

collision information –notification of a collision event to other system

components via the drive train CAN-bus or

a discrete collision output (conventionally wired)

Information about the occurrence of a crash is utilised by other control units for opening the central locking system, shutting off the fuel supply and activating the hazard warning light system, etc.

Rear collision detection

If the airbag control unit recognises a rear collision whose severity exceeds the predefined deployment threshold, then it ignites the belt tensioners and, where fitted, the battery isolation igniter.

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Crash sensors for side protection system

Side airbag crash sensors, G179, G180

(in the front doors)

For the first time in the Audi A3 Sportback, pressure sensors will be installed in the two front doors. In a side impact, the deformation of the vehicle causes a rapid increase in air pressure in the door cavity. This increase in pressure is detected by the sensor and signalled to the airbag control unit.

Rear side airbag crash sensors, G256, G257

(C-pillar)

The two rear side airbag crash sensors G256 and G257, which are installed in the C-pillar area on the left and right hand sides, are conventional acceleration sensors which are already being used in the Audi A3 3-door.

Side impact sensors for the side airbag are integrated in the front door

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Note

The a irbag control system uses sensors integrated in the front doors, etc. To avoid any impairment to the function of the side airbags, no modifications should be made to the doors and door trims (e.g. retrofitting of loudspeakers). Damage to the front doors can cause impairment of system functions. All work on the front doors should be referred to a specialist workshop.

Belt-on indicator

The new Audi A3 Sportback has the belt-on indicator function for driver and front passenger as known from the Audi A6 ´05.

For further information, refer to Self-Study Programme 323, Audi A6 ´05.

Seat belt warning system warning lamp

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Occupant protection

Airbag

Front airbags

Dual-stage gas generators are employed in the front airbags. The impact load acting on the driver and front passenger during an accident is reduced by radial inflation of the driver side airbag and by time-staggered ignition of the propellant charges. The airbag control unit controls the time interval between the two deployments depending on the severity and nature of the accident. The time interval can vary between approx. 5 ms and 40 ms.

In any event, both propellant charges are ignited. This ensures that no propellant charge remains active after an airbag deployment.

Driver airbag, N95, N250

The driver airbag uses two pyrotechnic propellant charges.

The a irbag control unit activates the electrical detonator of the first propellant charge. The detonator ignites the priming charge, which in turn detonates the actual propellant charge through nozzle holes in the gas chamber. The combustion of the propellant charge produces a pressure inside the gas generator. If the gas pressure exceeds a defined threshold, then the gas generator housing deforms and allows the gas to flow through the metal filter to the airbag. The airbag unfolds and is inflated by the gases resulting from combustion of the propellant charge. After a preset time delay, the airbag control unit energises the second electrical detonator, which directly ignites the secondary propellant charge. When a preset pressure is reached, the developing gas lifts the cap off the second-stage chamber and flows into the first-stage combustion chamber. From here, the gas flows through the filter to the airbag.

Propell ant charg e 1

Nozzle holes

Housing

Primi ng charg e Detonator 2

Detonator 1

Cap Propellant charge 1

Metal filter

Propell ant charge 2

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Ignition of the first propellant charge

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Ignition of the second propellant charge

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Occupant protection

Front passenger airbag, N131, N132

Unlike the driver airbag, the gas generator in the front passenger airbag works by the hybrid gas principle. The g as generator consists of two pyrotechnic propellant charges which are integrated in a pressurised gas bottle. The detonator activated by the airbag control unit ignites the first propellant charge by means of the priming charge. Should the pressure developing inside the gas bottle exceed a preset value, the rupture disc will explode and the gas mixture will inflate the airbag. The airbag is further inflated by the combustion of the second propellant charge . The coil springs ensure that the propellant charges burn as intended.

Detonator 1 Priming charge 1 Propellant charge 1 Coil spring Filter

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Detonator 2Priming charge 2 Propellant

charge 2

Coil spring

Rupture disc Pressurised gas bottle

Gas: argon approx. 98%

2% Pressure:approx. 250 bar

helium approx.

Side airbags, N199, N200

Like the airbags used in the Audi A6 ´05, the side airbags used in the Audi A3 Sportback are modules.

For further details, refer to Self-Study Programme 323, Audi A6 ´05.

So-called pyrotechnic tubular gas generators are used as gas generators. If the airbag control unit detects a side impact which meets the criteria for deployment, then it energises the relevant side airbag detonators. The primary charge is ignited by means of the priming charge. The developing gas flows through the metal filter into the airbag.

Air outlet Metal filter Priming charge

Air outlet Propell ant charge Detonator

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