254Service.AUDI A4´01 - Technical FeaturesDesign and FunctionSelf-study programme 254For internal use only.Advance by technologyThe new Audi A4, a vehicle which combines driving pleasure and good sense with the highest level of quality and sports styling.Control unit for vehicle electrical system...48New engine programme ...18Electronic stability programme with brake assistance ...32Steering column switch module ...44Crash sensors for front airbag ...14Multi-communication bar ...72Trapezium link rear axle...27Aero-floor ...72ContentsPage Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engine and gearbox2.0 l R4 and 3.0 l V6 engines (see SSP 255) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Innovations - 2.5 l V6 TDI engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Innovations - automatic gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2312Running gearAxles ............................................................ Mechanical unit mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brake assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 28 29 32Electrical systemVehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 CAN BUS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Steering column switch module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..44 Function circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Control unit for vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Function circuit diagram for "lowline" version . . . . . . . . . . . . . . . . . . . . . 50 Function circuit diagram for "highline" version . . . . . . . . . . . . . . . . . . . . 52 Convenience system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Anti-theft alarm system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Radio - chorus II, concert II and symphony II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Navigation IV and Navigation Plus-D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Multi-communication bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Electric logbook "Audi Logbook" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74Heater/ACDesign and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-piston compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glove compartment cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solar roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fresh air blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actuators/sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional diagram for fully automatic air conditioner . . . . . . . . . . . . . . Additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 77 78 79 80 81 82 84 86New The self-study programme will provide you with information on design and functions. It is not intended as a workshop manual. For maintenance and repair operations it is essential that you refer to the current technical literature.Important: Note3IntroductionThe architecture of motionPerformance and smooth running The engine programme of the new Audi A4 includes two petrol engines of a completely new design, with aluminium housings. The 2.0 litre 4-cylinder in-line engine with 96 kW (130 PS) and the 3.0 litre V6 with 162 kW (220 PS) fulfil the EU 4 emissions standard. A high degree of running smoothness is achieved via balancer shafts.Infinitely variable perfection For the first time in this vehicle class, Audi offers the infinitely variable "multitronic" automatic gearbox for all front-wheel drive versions.The new light alloy running gear With the four-link front axle, each wheel is controlled by four aluminium transverse links. The pivot bearings are also made from the same light alloy. The trapezium link rear axle for the quattro drive system is also used in the front-wheel drive models of the Audi A4.4Finely-tuned aerodynamics Despite the greater frontal area and the cooling air current for the air conditioner (standard), it was possible to improve the CD value by 5 %, in comparison to its predecessor, to 0.28. A special feature is the so-called aero-floor, which provides for optimal airflow on the underside of the vehicle.High safety standards With a thoroughly optimised body design and comprehensive safety equipment, the new Audi A4 is able to comply with all current valid safety standards, throughout the world. Crash sensors for the front airbags integrated directly into the bumper bar, improve occupant protection.Communication centre on wheels With regard to infotainment, the new Audi A4 leaves nothing to be desired. 4 different audio systems, 2 differently configured Navigation systems and a car phone with voice operation are on offer.SSP254_048Electronic stability programme (ESP) including brake assistant For the latest ESP generation, the hydraulic brake assistant is an integral part of the standard equipment. It is intended to assist the driver by automatically increasing the brake pressure during emergency braking.5IntroductionVehicle dimensions of Audi A4´011628901106/1101528 17661526 1937977951799445 L9212650 45272573039761400135710001088SSP254_051 69761050870471The aero-floornot only contributes to improved aerodynamics. It was also possible to reduce the noise level by approx. 3 dB (A). The aero-floor was designed so as to guarantee ground clearance and resistance to stone impact and to prevent accumulation of dirt, stones and snow.Front-wheel driveFour-wheel drive quattro and V6 engine SSP254_053Part of the additional costs generated by the aero-floor could be compensated by dispensing with certain panelling components as well as by dispensing with PVC protection of the underside of the vehicle. The latter is of advantage during recycling.The engine compartment noise insulation does not form part of the aerofloor.7BodyFront impact design features The new Audi A4 is designed for optimal conformance with current crash requirements and safety standards. This could only be achieved by increasing the body weight. In order to reduce this additional weight to a minimum, the proportion of light-weight materials has been increased in comparison to its predecessor. The proportion of high-strength sheet metal parts as well as the use of a total of 10 large component "tailored blanks", contribute significantly to weight reduction. Body rigidity has been increased by 45 % by increasing the number of connection points by 25 %. – the straightened longitudinal member with crash-optimised octagonal cross-piece – the rigid and significantly wider bumper cross-piece – the integration of the member structures into the passenger cell – strength, rigidity and weight-optimised suspension strut cross-pieceSSP254_054Depending upon vehicle weight, performance and fuel consumption are the characteristics which our customers can experience at first hand.8Side impact design features In the floor area, the cell consists of three large tailored blanks, which ensure a stable connection between the front and rear of the vehicle.Weight-saving optimisation of deformation characteristics in the event of a side impact was achieved by the use of an aluminium extruded profile in the sill.“tailored blanks” are made-to-measure sheet metal parts with varying material thickness.SSP254_055SSP254_056 9BodyDoors The doors of the Audi A4 demonstrate a significantly increased rigidity due to the onepiece door shell construction. For the first time, a so-called spray-on noise insulation is used, which is sprayed on as required and allows weight reduction for the same effectiveness.Noise insulationSSP254_067The newly developed sub-frame is bolted to the door shell via fitted bolts.SSP254_066 RoofIn addition, the doors have been fitted with a second weatherseal. One weatherseal is fitted to the door and the other is fitted to the body. The new door concept permits a reduction in the overall noise level of a further 3 dB (A) and thus contributes to improving the aero-acoustics.Roof trim strip Door window sealDoor window Door trim Door seal Door frame seal Door frame 10 SSP254_075Emergency door locking In the event of failure of the central locking, e.g. due to power supply faults, each door can be individually locked without using the lock cylinder. Firstly, with the door open, the cap must be removed. Emergency locking is effected by inserting the ignition key. After the door has been closed, it is not possible to open it from the outside. The door can be opened from the inside by actuating the door release handle twice. Luggage compartment lid The luggage compartment lid should always be operated via the radio remote control. The lock cylinder for the luggage compartment lid is integrated into the handle.SSP254_069Continuous locking of luggage compartment If the lock cylinder is in the horizontal position with the key removed, the luggage compartment lid is no longer included in the central locking system. Opening is then only possible via the centre unlocking button of the radio remote control. When the lock cylinder is in the vertical position, the lid is an integral part of the central locking system.SSP254_070SSP254_071Manual unlocking and opening is effected by turning the key to the left. In this position, it is not possible to remove the key, which must subsequently be returned to the vertical position. Thus, it is ensured that the luggage compartment lid is an integral part of the central locking system.SSP254_072 11Occupant protectionOverview of systemG 283G 284J162 J220 J285/K75K145AIRBAGOFFJ533AIRBAGE224T16AUS EINN95 N131J393J234J526N199N200G179N153N154G180N201N202N277 G 256N278 G 257SSP254_02912To complement the comprehensive body modifications, occupant protection has been improved through the further development of the familiar 8.4 airbag system.The system comprises driver/passenger airbags, front side airbags, optional rear side airbags, SIDEGUARDS®, three point front seat belts with ball tensioners and belt force limiters, three point rear outer seat belts, centre lap belt (for fixed rear seat bench), Isofix preparation in rear of vehicle, and a total of 6 non-central accelerometers: – 2 front impact crash sensors – 2 driver/passenger side airbag crash sensors, (in the B-pillar for side impact) – 2 driver/passenger rear side airbag crash sensors, (on the C-pillar for side impact)The new generation bears the designation 8.4 E, where the E stands for "extended".The position of the sensors is selected so that they are installed as near as possible to the outer structure of the vehicle. This enables quicker deceleration detection in the event of an impact.The external sensors deliver digitised acceleration data to the airbag control unit, which is then evaluated in the control unit and which triggers the relevant restraint system components.Key E224 G179 G180 G256 G257 G283 G284 J162 J220 J234 J285 J393 J526 J533 Key switch for switching off passenger’s side airbag Side airbag crash sensor, driver’s side (B-pillar) Side airbag crash sensor, passenger’s side (B-pillar) Crash sensor for rear side airbag, driver’s side Crash sensor for rear side airbag, passenger's side Front airbag crash sensor, driver’s side Front airbag crash sensor, passenger’s side Heater control unit Control unit for motronic Airbag control unit Control unit with display unit in dash panel insert Central control unit for convenience system Control unit for telephone / telematics Diagnosis interface for data bus (Gateway) K75 K145 N95 N131 N153 N154 N199 N200 Airbag warning lamp "Airbag off" warning lamp, passenger's side Airbag igniter, driver's side Airbag igniter 1, passenger's side Igniter for belt tensioner, driver's side Igniter for belt tensioner, passenger's side Igniter for side airbag, driver’s side Igniter for side airbag, passenger's side Igniter for rear side airbag, driver’s side Igniter for rear side airbag, passenger's side Igniter for airbag in B-pillar (SIDEGUARD®), driver's side Igniter for airbag in B-pillar (SIDEGUARD®), passenger's side Connector, 16-pin, diagnosis connectionN201 N202 N277 N278 T1613Occupant protectionCrash sensors for front airbag G283, 284 Both sensors for front impact detection function in conjunction with the crash sensor and the safe sensor which are integrated into the airbag control unit J234. If a certain signal threshold is exceeded in the front airbag crash sensor, a threshold reduction is activated in the airbag control unit, which results in a shorter triggering time.Upper body HeadSSP254_058Triggering of belt tensionersTriggering of front airbagsFront airbags inflated Belt force limiter responseDamping function response in the steering columnDeceleration loadImpactTime [ms]SSP254_06314SSP254_064Vehicle reboundCrash sensors for side airbags G179, 180, 256, 257 In order to trigger the components of the restraint system, two simultaneous impact detection signals are required for the plausibility check: – from both opposing crash sensors (B-pillar left with right and/or (C-pillar left with right) and – from the control unit internal crash sensors.The crash sensors are designed in such a way that incorrect installation is excluded.SSP254_059Airbag control unit J234 The warning lamp for airbag K75 is activated continuously following a detected impact. "CRASH DATA STORED" and the triggered components are displayed with fault code during fault memory readout. Re-encoding of the airbag control unit is no longer possible after the first crash data message is stored. Triggering is performed in two thresholds depending upon the deceleration value: – Threshold 1 = belt tensioners only – Threshold 2 = belt tensioners and airbag(s)Sensors and components to be replaced following an accident, are listed in the current workshop manual.15Occupant protectionDeactivation of passenger airbag Deactivation of the passenger airbag is only possible via the key switch. In the Audi A4, the passenger's side airbag is also deactivated. Deactivation via the diagnostic tester is not possible. If a customer requires the deactivation function where a key switch is not fitted, this can only be achieved by retrofitting the key switch and airbag OFF lamp and by re-encoding of the airbag control unit.SSP254_101Front belt attachment Belt lock and strap fastenings are permanently connected to the seat frame. Thus, in conjunction with the seat belt height adjuster, an optimal belt fitting can be achieved for each seat position.SSP254_011Front head restraints In order to offer a high degree of occupant protection in conjunction with the seat belt and airbag, the front head restraints have been supplemented by an integral locking mechanism.SSP254_10216Crash signal processing There are two separate crash signal outputs: One crash signal is output via the conventional wiring and triggers the following functions: – Transmitting an emergency call via the control unit for telephone/telematics J526 (optional) – unlocking the vehicle, – Switch on interior light (switch must be set to door contact), – switching on hazard warning lights via the central convenience electronics J393. The auxiliary heater J162 (optional) is switched off by the central convenience electronics J393 via a CAN convenience message. The second crash signal output functions via the convenience CAN bus, which switches off the engine fuel supply via the engine control unit J220.17Engine and gearboxEngineThe 4-cylinder, 2.0 l engine provides high propulsive force due to the maximum torque of 195 Nm at 3300 rpm.Torque [Nm]SSP254_038Engine speed in rpmSSP254_060The 3,0 l V6 engine with five-valve cylinder head, produces162 kW (220 PS) at 6300 rpm from 2976 cm3. The maximum torque of 300 Nm is developed at 3200 rpm.Power output [kW] Engine speed in rpm SSP254_061SSP254_030Detailed information on these engines can be found in SSP 255.18Power output [kW]Torque [Nm]Innovations 2.5 l V6 TDI engineSSP255_045Engine speed in rpmSSP255_039Technical data Capacity: Bore: Stroke: Compression: Power output: Torque: 2496 cm3 78.3 mm 86.4 mm 18.5 : 1 132 kW (180 PS) 370 Nm at 1500 rpm Injection system: Turbocharger: Exhaust emissions class: Consumption: (6-gear, quattro) Bosch VE VP 44 S3.5 VNT 20 EU 3 urban country average 11.0 l/100 km 6.1 l/100 km 7.8 l/100 kmThe main features of the basic engine are the same as those of the familiar V6 TDI engine with 132 kW (180 PS). Power output and torque curve values could be maintained under conditions which were well within EU 3 limit values.The injection system was modified in order to reduce exhaust gas and particle emissions.Limit value [%]EU 3 limit values 100 % Particle CO HC+NOx NOx = 0.05 g/km = 0.64 g/km = 0.56 g/km = 0.50 g/kmNOxHC+NOxCOParticle SSP255_038 19Power output [kW]Torque [Nm]Engine and gearboxInjection pump VP 44 S3.5Forced flush return Distributor bushingDistributor shaftSolenoid valveSupply piston Thermal shoulder Forced flush feed SSP255_040The high pressure section of the injection pump has been redesigned with regard to pressure levels and quicker solenoid valve actuation. The injection pressure at part throttle has been increased by the following measures: – increased cam stroke from 3.5 to 4.0 mm – more stable support structure for high pressure section on pump body – conversion from 3 pistons with a diameter of 6.0 mm, to 2 pistons with a diameter of 7.0 mm. By reducing the number of high-pressure pistons from 3 to 2, it was possible to reduce high-pressure leakage via the sealing surfaces.In order to initiate pre-injection for cold and warm engines, the solenoid valve dynamics have been significantly increased. The associated increased heat generation in the solenoid valve, is compensated by improved fuel flow and optimal filling of the high pressure section is achieved. Noise levels have been significantly improved by the pre-injection for cold and warm operation and the use of dual-spring nozzle holders.Previously, pre-injection via the solenoid valve was only realised during the engine warm-up phase.20Injector For the first time, an ICU injector (Inverse Cavity Undercut) is used, which has a dual needle guide. The advantage of this ICU geometry is a significantly improved spray formation, especially in the part throttle range for small injection quantities and short needle lift. Due to the improved spray formation through the use of the ICU injector, it was possible to reduce the exhaust emissions and the particle values by up to 20 %.ICU seat geometrySSP255_041Dual needle guideICU seat geometryStandard seat geometrySSP255_04221Engine and gearboxCharge air coolerThrough duct Cooling duct sectionSSP255_043The existing series connection of the two charge air coolers for the 110 kW engine is inadequate for the 132 kW engine with its high air throughput. A new charge air cooler design was developed, in order to ensure optimal charge air flow.The charge air cooler design comprises two sections, in which part of the charge air is fed via a through duct, connected to a space-saving pipe, to the section of the other charge air cooler which is fitted with cooling fins. The rest of the charge air is fed directly through the cooling fins, via a separate pipe, to the second charge air cooler and into the through duct.22Innovations - automatic gearbox5-speed 01V automatic gearbox The Audi A4 quattro MJ01 with 5-speed automatic gearbox features a new shift lever gate, together with a new shifting concept. The existing selector lever positions, 4,3,2 are discontinued and are replaced by the "S" position. Gearshift positions 4,3,2 have been discontinued as they are hardly ever used in practice. The DSP (dynamic shift programme) and "tiptronic" function have basically rendered them superfluous. With the selector lever is in the "S" position, a sports shift programme provides the relevant driving dynamics. In position "S", the DSP also provides for adaptation of the driving set values to the driving conditions. The introduction of the "S" programme enables a significant extension of the useful shift range between economy and sports. The "S" programme comprises the following special features: – If, during driving with constant accelerator pedal position, the selector lever is set to the "S" position, the system always shifts down, within defined limits. – In order to achieve a direct driving reaction in response to accelerator pedal actuation, the converter clutch is closed during driving operation, where possible. – If, in conjunction with the overall gearbox ratio, 5th gear is designed as overdrive gear (overdrive, 4+E), only 1st -4th gears are shifted. We recommend the multi-function steering wheel (available as optional extra) with steering wheel "tiptronic" ("thumb shifting").Example: Dynamics code 40 Shift map 1 SSP254_117PR+NDSThrottle valve angle [%]Gearbox output speed [rpm] D - normal driving programme S - sports driving programme SSP254_10323Engine and gearbox"multitronic" and 5-speed automatic gearboxSSP254_088An innovation for all automatic gearboxes is the "Tip in D " function. This means that the steering wheel "tiptronic" function is now also available in selector lever position "D". The transition to the "tiptronic" function is effected by actuating one of the two tip switches on the multi-function steering wheel (selector lever in position "D"). The system then switches to the "tiptronic" function for approx. 10 seconds. All gears can be shifted within the range of permissible engine speeds. The system returns to normal automatic operation approx. 10 seconds after the last tip request.Special feature: The countdown from approx. 10 seconds to return to normal automatic operation is interrupted, in the event that cornering is detected or the vehicle is in overrun operation. When normal driving conditions are detected again, the countdown recommences from approx. 10 seconds.24Notes25Running gearAxlesFour-link front axle The thorough further development of the light-weight construction resulted in a weight reduction of approx. 8.5 kg at the front axle. In addition to all transverse links, the pivot bearing is now also made of aluminium. The wheel bearing is attached to the pivot bearing via four bolts. The wheel hub can be pressed in and out.Aluminium spring plateAluminium mounting bracket Shock absorber valvesSSP254_087Aluminium pivot bearingSSP254_086The suspension strut mounting is of the bulky rubber bearing construction. It consists of two functional components: – The inner part forms the connection to the piston rod. – The larger outer part provides for acoustic insulation of the shock absorber.SSP254_085 26Trapezium link rear axle The rear axle design with largely identical components is used in both the front-wheel drive as well as in the quattro versions. Apart from the axle mounting, the two axle versions differ only in the wheel carrier and the wheel bearings.Camber adjustmentSSP254_089 Toe adjustmentThe front-wheel drive version is fitted with a wheel bearing unit with integral wheel hub, which is mounted on a stub axle forged together with the wheel carrier.SSP254_083Camber adjustmentSSP254_091 Toe adjustmentThe wheel bearings of the quattro version consist of pressed-in, double-row angular ball bearings with conventional wheel hubs.SSP254_082 27Running gearMechanical unit mountingsEngine mounting 1Cross memberTorque memberGearbox mounting 3SSP254_107 Engine mounting 2A newly designed three-point mechanical unit mounting is used in the new Audi A4. The hydraulically damped engine mountings (electrically-controlled version for diesel engines) are fastened directly to the longitudinal members via die-cast aluminium brackets. The gearbox mounting is effected by means of a conventional rubber bearing on a bodymounted aluminium carrier, which is produced according to the hollow sand casting technique.The additional cross member enables support over a longer lever arm, which positively influences vibration and load cycle characteristics. The aluminium cross member is bolted to the body as well as to the rear subframe mountings and, in addition to its supporting function for the gearbox mounting, serves as a body-stiffening tunnel bridge.The three-point mechanical unit mounting is used for all engine/gearbox combinations except those including the 01V 5-speed automatic gearbox.28Brake systemThe new Bosch ESP 5.7 is introduced in the Audi A4. The ESP 5.7 is distinguished by the following special features: – The hydraulic unit and control unit form a single unit. – The charging pump (actuation of ESP hydraulic pump V156) is discontinued. – A brake assistant is included.Hydraulic modulator Due to the increased brake fluid viscosity at extremely low ambient temperatures, the required delivery rate for the return pump for ABS V39 could not be achieved without a charging pump (resulting from the increased suction resistance in the system). The purpose of the development of the ESP 5.7 was to improve the suction of the ABS return pump so that the charging pump was no longer necessary. The charging pump could be discontinued through the use of a two-stage ABS return pump, enlarging the cross-section of the brake lines and the use of a larger-dimensioned central valve in the brake master cylinder.SSP254_09429Running gearSingle-stage ABS return pumpSuction volumesUTOTUTOTUTSuction volumesUTOTUTOTUTSSP254_095The graphic shows a comparison of the suction volumes of both pump versions. In the single-stage ABS return pump, the entire suction volume must be drawn in and flow through the suction line during one piston stroke (piston stroke from TDC to BDC). The suction pressure is correspondingly high and increases with increasing viscosity. Cavitation and the associated drop in performance on the pressure side, are the results.30Two-stage ABS return pumpWorking chamber 2Suction volumesWorking chamber 1UT OT UT OTUTOTUTOTSSP254_096The piston of the two-stage ABS return pump is stepped and has a double-acting function within two working chambers. Suction is effected in two stages; brake fluid being drawn through the suction line during each piston stroke.As the entire suction volume is supplied almost continuously, the maximum suction flow rate is significantly lower, which diminishes the suction pressure and prevents cavitation. Thus, a quick pressure build-up is ensured, even at extremely low temperatures.Function: If the piston moves from BDC to TDC, the brake fluid in working chamber 1 is compressed whereas working chamber 2 is simultaneously under suction. If the piston then moves from TDC to BDC, the brake fluid which has been drawn into working chamber 2 is forced back into the suction line against the inlet valve. In working chamber 1, brake fluid is now drawn via the open inlet valve, out of the suction line and out of the connection line to working chamber 2. The suction flow rate in the suction line is diminished by that amount which flows back out of the connection line from working chamber 2 (drawn in during previous working operation).31Running gearBrake assistantInvestigations in accident research have shown, that the majority of drivers fail to adequately actuate the brakes in an emergency situation. This results in insufficient brake pressure being generated to achieve maximum vehicle deceleration. This lengthens the braking distance. During emergency braking, the brake assistant aids the driver by increasing the brake pressure automatically, to a level exceeding the locking limit. The ABS (Anti-lockbrakingsystem) is thus quickly brought into the operating range, which enables a maximum vehicle deceleration to be achieved.Brake servo pressure sensor G294 is used for detection of emergency braking.Pressure sensor G294SSP254_093For this purpose, the pressure increase gradient (pressure build-up with respect to time) is evaluated and, if necessary, the brake assistant is activated.Pressure [p]Time [t] SSP254_092 Emergency braking Normal braking distance32The function of the brake assistant is sub-divided into 2 phases: • Phase 1 If the pressure increase gradient exceeds a specified value (emergency braking), the ABS return pump and the relevant solenoid valve are activated by the ESP control unit and the brake pressure is thus increased into the ABS control range, in a similar manner to that of the control system for an electronic differential lock. • Phase 2 If the pressure determined by the driver falls below a certain value after triggering of the brake assistant, the system pressure is restored to the pedal pressure determined by the driver.Brake assistant activatedBrake pedal unloadedBrake assistant switches offPhase 1Phase 2Brake pressure [p]ABS control rangeTime [t]SSP254_084Brake pressure determined by an experienced driver Regulated brake pressure (brake assistant) Determined brake pressure insufficient inexperienced driverThe integral inlet and outlet valves in the hydraulic modulator are no longer simply switched on/off, but are regulated via supplied voltage. This enables more precise control on extremely slippery surfaces, e.g. ice.33Running gearBrake fluid reservoir The brake fluid reservoir is secured with an additional screw. The new maintenance opening in the brake fluid reservoir enables the extraction of brake fluid from both brake fluid chambers. The new brake filler and bleeder unit VAS 5234 must be used for this purpose.SSP254_098 Fastening screwMaintenance openingBrake light switch The fastening and adjustment of the brake light switch are new. The brake light switch is secured to the pedal bracket via a bayonet fitting. The position of the push rod is adjusted for the basic setting. For this purpose, the brake light switch must be released by turning it anti-clockwise. The push rod catch is released simultaneously via the locking lug. The push rod is now free and can be adjusted without risk of damage. The push rod is pulled out to the stop for the basic setting. The brake light switch can now be inserted into the pedal bracket and secured by turning clockwise. At the same time, the push rod catch is locked automatically by means of the locking lug.SSP254_09934Notes35Electrical systemVehicle electrical systemControl unit for telematics J499 Control unit for headlamp range control J431 Chip card reader R99Control unit for mobile phone control electronics J412Battery Control unit with display in dash panel insert J285Front airbag crash sensor, passenger’s side G284Control unit for coolant fan, Stage 1+2 J293Control unit for ESP J104Front airbag crash sensor, driver’s side G283 Control unit for Motronic J220 Control unit for automatic gearbox J217 36Steering column switch module J527Side airbag crash sensor, passenger’s side G180Door control units, passenger side J387 rear right, optional J389Side airbag crash sensor, rear driver’s side G256 passenger’s side G257Control unit for trailer recognition J345Control unit for parking aid J446Control unit for tyre pressure monitor J502Airbag control unit J234Central control unit for convenience system J393 Side airbag crash sensor, driver’s side G179 ESP sensorSSP254_008Door control unit, driver’s side J386, rear left, optional J388 Control unit for vehicle electrical system J519 37Electrical systemCAN BUS networkingJ285GatewayDiagnosis system J507 J386 J220 R99 J387J217J388J389 J499J526 J104 J393 J502TRACK SEEK EJECT FR FF TUNE CD1SCAN AS TPCDC AM FM21 EJECT BASS23456Audi symphony MIDDLE TREBLEDOLBY SYSTEM12BALANCEFADERRDS RANDOMPLAYTAPESDEJ234 E87 J162RNOX sensor (USA only) J345 J446 J401J527 J402 J519 G85 J527+J136 R94R T38The ignition switch signals and the control buttons for multifunction and "tiptronic" steering wheel are registered via the steering column electronics.J453CAN data bus The Audi A4 is equipped with a widely extended CAN data bus system. Due to the ever increasing number of control units installed in the vehicle and the associated requirement for data exchange, the importance of the CAN data bus system increases significantly.For communication between the installed control units and the diagnostic tester, two diagnosis wires (K and L) are available.G85 E87 J104 J136 J162 J217 J220 J234 J285 J345 J386 J387 J388 J389 J393 J401Steering angle sender Operating and display unit for air conditioner Control unit for ESP Control unit for seat adjustment with memory, optional Auxiliary heater, optional Control unit for automatic gearbox Control unit for motronic Airbag control unit Control unit with display unit in dash panel insert Control unit for trailer recognition Door control unit, driver’s side Door control unit, passenger side Rear left door control unit, optional Rear right door control unit, optional Central control unit for convenience system Navigation system control unitJ402 J446 J453 J499 J502 J507 J519 J526 J527 R R94 R99Control unit for operating electronics, navigation, TV tuner Control unit for parking aid Control unit for multi-function steering wheel Control unit for telematics Control unit for tyre pressure monitor Control unit for speech entry Control unit for vehicle electrical system Control unit for telephone permanent installation Control unit for steering column electronics Radio Interface for navigation Chip card readerDrive BUS 500 kBaud Convenience BUS 100 kBaud Display BUS 100 kBaud Diagnosis connection K wire Diagnosis connection L wire (2nd K wire)The newly developed adapter VAS 6017 enables communication with all control units.SSP254_112 39Electrical systemDash panel insertCruise control system ONAuto-check system Setting buttons for digital clock, date and instrument illuminationSSP254_012Call-up button for Reset button for trip service interval recorder indicatorThere are two dash panel insert versions: – "lowline" – "highline" The "highline" version is equipped with a high-quality colour display for the driver information system and is installed in vehicles with navigation systems as well as telematics.The dash panel insert of the new Audi A4 is equipped with – the gateway for linking the three data bus systems: drive, convenience, information – and the immobiliser III.40User prompt in the centre display via the control switch in the centre console, is only available in vehicles with – navigation system ("highline" version only) and/or – telematics and/or – auxiliary heater and/or – tyre pressure monitoring.The optional driver information system includes the following functions: – radio clock – auto-check system – on-board computer.SSP254_104The km range is indicated in the basic version.In order to ensure good signal reception for the radio clock, the receiver is installed in the rear bumper bar.V +5 h r al Ea t sig n o i d RaSSP254_10841Electrical systemA new feature of the Auto-Check system is the position-dependent bulb monitor display. The fault message is transmitted from the vehicle electrical system control unit J519, via the convenience data bus, to the dash panel insert J285 and appears on the centre display.SSP254_118Control unit with display unit in dash panel processor J285Convenience data bus Control unit for vehicle electrical system J519SSP254_125The Audi A4 quattro is equipped with two fuel gauge senders G and G169. Sender G registers the lower, and sender G169 the upper partial volume in the fuel tank. The signals from senders G and G169 are evaluated separately. The calculated litre values are then added and displayed.SSP254_123 Fuel gauge sender G Fuel gauge sender 2, G16942DiagnosticsControl unit with display unit in dash panel insert J285Convenience data busControl unit for steering column electronics J527Terminal 15Ignition lock D SSP254_138The dash panel insert checks the plausibility – of both fuel gauge senders in quattro vehicles – as well as the terminal 15 input signal.Due to the gateway function of the dash panel insert, the communication with the individual control units connected to the CAN data bus is checked during diagnosis. Communication faults are entered into the fault memory. The current status can be read in the measured value blocks.A further innovation is the display of the maximum and minimum engine oil levels in the measured value block after the most recent service operation. The adaptation of the mileage/kilometre reading after replacement of the dash panel insert, is possible (several attempts) up to a recorded distance of 5 km after installation.43Electrical systemSteering column switch moduleDue to the compact design of the newly developed steering column switch module, it was possible to minimise the amount of wiring necessary and the space requirements. A self-diagnosis facility for the steering column switch is now available with new switch module. The steering column switch module consists of the following components: – Turn signal switch – Wiper switch with interval potentiometer – Separate steering column switch cruise control system operation – Coil spring for diver's airbag – Steering angle sensor for ESP – Steering column electronics for signal conversion and processing of drive and convenience CAN BUS J527 In addition, the steering column electronics register the ignition switch signals. Furthermore, the control buttons for multifunction and "tiptronic" steering wheel are registered via the steering wheel electronics module. Steering column switch Detection of the respective switch positions is effected via voltage coding, using various resistance values in the relevant position. The steering column electronics evaluates this switch information and transmits it, via the convenience CAN BUS, to the vehicle electrical system control unit J519. Cruise control system (CCS) For ergonomic reasons, the control switch for the cruise control system is located on the left side of the steering column, below the turn signal lever. Warning lamp K31 in the dash panel insert illuminates when the CCS is in control mode. The modified operation of the CCS Steering column switch function is described in the Owner's Manual.44 Ignition steering lock Cruise control system E45 Steering column electronics J527Turn signal switch E2SSP254_105Ignition lock registration The signals from the terminals: – – – – – P 86s 75 15 50 parking light ignition key contact Load-reduction relay ignition ON starterWiper switch ESteering angle sensor G85are transmitted to the steering column electronics J527 via conventional wiring. The switch positions of the ignition lock are prepared by the electronics, supplied to the convenience CAN bus and then transmitted via the gateway to the drive and infotainment CAN bus systems.Steering angle sender G85 The determination of steering angle is performed via optical elements in the steering column electronics J527 and is supplied to the drive CAN BUS. The current steering angle position is thus made available to the ESP control unit.Coil springFor further information on the optical steering angle sensor, please refer to SSP 204.Self-diagnosis Communication between the diagnostic tester and the steering column electronics J527 is effected by means of the convenience data bus via the central convenience electronics J393, as no separate K wire is connected to the steering column electronics.. (see graphic 254 018 on Page 57) The steering column electronics module with operating unit for "tiptronic", multi-functions, horn etc., is incorporated in the self-diagnosis. Address word 16 The steering column switch module must always be coded. After the addressing, the tester answers with the text "steering column electronics".45RTSteering column electronics module J453 with operating unit E221 SSP254_014Electrical systemFunctional diagram Steering column switch module (maximum equipment)Colour coding Components E E2 E45 E221 G85 H J234 J453 J527 S Z36 Windscreen wiper switch Turn signal switch CCS switch Operating unit in steering wheel Steering angle sender Horn actuation Airbag control unit Control unit for multi-function steering wheel Control unit for steering column electronics Fuse Heated steering wheel = Input signal = Output signal = Positive power supply = Earth = CAN-BUSAuxiliary signals 1 2 3 4 5 6 7 8 9 10 11 12 13 CAN screen drive Emergency vehicle distress radio Emergency vehicle radio Cruise control system on/off CAN low convenience CAN high convenience CAN low drive CAN high drive Ignition lock terminal 75 Ignition lock S contact Ignition lock terminal 15 Ignition lock terminal 50 Ignition lock terminal PY Z46{XConnection within the functional diagram+S13/ 10A J453R/TH E221Z36 G85123 Z Y45678J234XJ527ZX Y910111213E45E2E3131inoutElectrical systemControl unit for vehicle electrical system J519The control unit for vehicle electrical system J519 is the newly developed electronic central electrics and comprises a comprehensive self-diagnosis, which can be selected directly with address word 09. The control unit for vehicle electrical system receives the input signals from the convenience CAN BUS via the steering column switch module or the rotary light control. The power connections for the individual consumers are driven via semi-conductor elements, e.g. transistors. A separate supply is not required, as this is provided by the internal electronics in the event of a fault.Control unit for speech entry J507J4 Dual tonehorn H2/H4Pb1J0915105ACWiper system Power supply Control unit for vehicle electrical system J519Hazard warning lights switch E3Rotary light control E1Lighting systemRelay for X contact J18 Steering column electronics J527Control unit for trailer recognition J345 SSP254_068 Dash panel insert J28548There are three control unit versions: – "lowline" for the standard version – "lowline" for vehicles with headlight washer system – "highline" for vehicles with driver information systemThe following functions are available with the "lowline" version: – – – – – – – Wash/wipe control and interval Hazard warning and turn signal control Actuation of horn and load-reduction relay Parking light left/right Side light left/right Main beam left/right and headlight flasher Number plate lightThe "highline" version implements the driver information system function and also performs the following control functions: – – – – Driving light and dipped beam left/right, Fog lights and rear lights, Reversing lights, Brake lightswith separate outputs to each of the individual consumers.Light control In the highline version, light control is transmitted from the steering column switch module or directly from the rotary light control, via the convenience data bus, to the vehicle electrical system control unit.Side lights Dipped beam*Control unit for vehicle electrical system J519Fog lights* Rear fog lights*Parking lights Main beam Headlight flasher*Inthe "lowline" version, the components marked with an asterisk are connected via conventional wiring and fuses, directly to the lighting units.49Electrical systemFunctional diagram Control unit for vehicle electrical system J519"lowline" version Components V11 E1 E3 F F4 F216 H2 H7 J4 J59 J345 J446 J519 L22 L23 L46 L47 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M16 M17 M18 M19 M25 M29 M30 M31 M32 S U10 V V5 Light switch Hazard warning light switch Brake light switch Reversing light switch Contact switch for switchable rear fog lights Treble horn Bass horn Relay for dual tone horn Load-reduction relay for x contact Control unit for trailer recognition Control unit for parking aid Control unit for vehicle electrical system Bulb for fog light, left Bulb for fog light, right Bulb for rear fog light, left Bulb for rear fog light, right Bulb for side light, left Bulb for rear light, right Bulb for side light, right Bulb for rear light, left Bulb for turn signal light, front left Bulb for turn signal light, rear left Bulb for turn signal light, front right Bulb for turn signal light, rear right Bulb for brake light, left Bulb for brake light, right Bulb for reversing light, left Bulb for reversing light, right Bulb for side turn signal light, left Bulb for side turn signal light, right Bulb for high-level brake light Bulb for dipped beam headlight, left Bulb for main beam headlight, left Bulb for dipped beam headlight, right Bulb for main beam headlight, right Fuses Socket for trailer operation Windscreen wiper motor Windscreen washer pump V48 V49 X Pump for headlight washer conditioning system Servo motor for headlight range control, left Servo motor for headlight range control, right Number plate lightsColour coding = Input signal = Output signal = Positive power supply = Earth = CAN-BUS Auxiliary signals 1 2 3 4 5 6 7 A U X Y Z CAN high convenience CAN low convenience Terminal 75 not fitted with trailer coupling only with trailer coupling Automatic gearbox "multitronic" Manual gearbox50{Connection within the functional diagram30 X H2 H7 E1 J590 1 2S36 30AS37 20AS19 15AS14 10AS20 15AS40 25AFM25L47 M17 M10 M2 M8M19M7 M3 M32 M31 V49L22L23J458s U X Z Y5Z4J51930X15S27 30AS77 30AA 155 6S21 15AYJ345U57321M M MA J4465X X F4 L46 M16 M9 M4 M6 M18 M5 M1 M30 M29 V48 V5 V11 V E3F216 U10in outElectrical systemFunctional diagram Control unit for vehicle electrical system J519"highline" version Components V11 E1 E3 F F216 H2 H7 J4 J59 J345 J446 J519 L22 L23 L46 L47 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M16 M17 M18 M19 M25 M29 M30 M31 M32 S U10 V V5 Light switch Hazard warning light switch Brake light switch Contact switch for switchable rear fog lights Treble horn Bass horn Relay for dual tone horn Load-reduction relay for x contact Control unit for trailer recognition Control unit for parking aid Control unit for vehicle electrical system Bulb for fog light, left Bulb for fog light, right Bulb for rear fog light, left Bulb for rear fog light, right Bulb for side light, left Bulb for rear light, right Bulb for side light, right Bulb for rear light, left Bulb for turn signal light, front left Bulb for turn signal light, rear left Bulb for turn signal light, front right Bulb for turn signal light, rear right Bulb for brake light, left Bulb for brake light, right Bulb for reversing light, left Bulb for reversing light, right Bulb for side turn signal light, left Bulb for side turn signal light, right Bulb for high-level brake light Bulb for dipped beam headlight, left Bulb for main beam headlight, left Bulb for dipped beam headlight, right Bulb for main beam headlight, right Fuses Socket for trailer operation Windscreen wiper motor Windscreen washer pump V48 V49 X Pump for headlight washer conditioning system Servo motor for headlight range control, left Servo motor for headlight range control, right Number plate lightColour coding = Input signal = Output signal = Positive power supply = Earth = CAN-BUSAuxiliary signals 1 2 3 4 U CAN high convenience CAN low convenience Terminal 75 Terminal 31 Connection within the functional diagram5230 15 H2 H7 E1 J59 FAS36 30AS37 20AS14 10AS7 10AS40 25A012M25L47M17M10 M2 M2 M8M19M7 M3 M32 M31 V49L22L23J41558sUJ5193015S27 30AS77 30AJ345U321M M M4X J446 X L46 M16 M9M4 M4 M6 M18 M5 M1 M30 M29 V48 V5 V11 V E3F216 U10in outElectrical systemIn the "highline" version of the vehicle electrical system control unit, only the 21 watt filament of the two-phase bulb for the brake and rear light is used. With lights switched on and non-actuated brakes, the power rating is reduced to 5 watts by a pulse-width modulated signal via the vehicle electrical system control unit J519. Thus a self-diagnosis/driver information system (FIS) is possible for the second rear light. A defective brake light would be indicated in FIS.Rear lights on:Brake actuatedMeasuring equipment DSO5 V/Div.= 10 ms/Div.Recorder operationPhotoChannel AChannel BTrigger modeTMeasuring mode Cursor 10Cursor 2PositionTime/Div.MultimeterSkipPrintHelpBrake not actuatedSSP254_080In vehicles with the "highline" version, national lighting regulations can be adapted via coding.For non-plausible condition of the rotary light control, the side lights and low beam are switched on automatically by the vehicle electrical system control unit in the "highline" version.Electrical fault finding In certain lighting circuits, an open-circuit voltage measurement using the Multimeter is not possible, as the semi-conductor elements are clocked until the circuit is again closed. For defective bulbs which are operated via the vehicle electrical system control unit J519, no permanent fault storage is effected, but only for the period of the fault. This means that the fault memory must not be erased after changing a defective bulb.1 2Position Time/Div.MultimeterReversing lamp on:Measuring equipment DSO5 V/Div.= 2 s/Div.Recorder operationPhotoChannel AChannel BMeasuring mode Cursor 10Cursor 23Vehicle self-diagnosisPrintHelpSSP254_052 1 - bulb illuminates 2 - bulb failure 3 - clock frequency of power output54Turn signal/hazard warning light control The functions: – Anti-theft alarm flasher – Central locking system flasher when opening/closing – Key-learn flasher for key adaption – Crash flasher – Panic flasher (USA only) are specified by the central convenience electronics and transmitted via the convenience data bus to the vehicle electrical system control unit, which then executes the "commands". The hazard warning flasher signal is controlled separately by the vehicle electrical system control unit, via the hazard warning flasher button. If, during hazard warning flashing, the turn signal flasher is actuated, e.g. during towing, the hazard warning lights lose their priority for this period. The turn signal clicking is generated by an integral acoustic relay in the dash panel insert. For active hazard warning flasher with ignition OFF, the flasher bulbs are actuated for a shorter period in order to minimise current consumption.Turn signal light, right Turn signal light, left SSP254_077The signal for turn signal flashing or motorway flashing is output via the steering column switch module and executed by the vehicle electrical system control unit.Motorway flashing is detected by the vehicle electrical system control unit when the turn signal lever is pressed and this triggers a triple turn signal flash.Turn signal light, right Turn signal light, left SSP254_07855Electrical systemWash/wipe system The wash/wipe system is equipped with the speed-dependent 4-stage interval system. A new feature is the re-wipe function for the windscreen washer system. Re-wiping occurs automatically 5 seconds after the wash procedure is completed. The windscreen wash/wipe relays are integrated into the vehicle electrical system control unit J519. The washer fluid reservoir is a two-part design for easier removal and installation. An additional sensor is fitted for vehicles with headlight washer system (HWS). In the "highline" version, this is also used for the Check system. The purpose of the sensor, is to switch off the HWS pump via the vehicle electrical system control unit. This prevents the pump running dry.Reservoir in engine compartment Reservoir in front left wheel housingConnectedWindscreen and rear screen washer pump V58 Headlight washer system pump V11 56Windscreen washer fluid level sender G33SSP254_024Control unit for trailer recognition J345 A separate control unit is required for trailer operation. This transmits the vehicle lighting system convenience CAN messages from the vehicle electrical system control unit to the trailer lights. A parallel link from the trailer socket to the vehicle wiring would result in fault detection via the microprocessor in the vehicle electrical system control unit. The diagnostic function of the control unit for trailer recognition is performed via the vehicle electrical system control unit J519, address word 09.SSP254_016Address word 09 - vehicle electrical system/ Central convenience electronics Communication takes place by means of the convenience data bus via the central convenience electronics, as no separate K-wire leads to the vehicle electrical system control unit. For this reason, intact central convenience electronics are essential for performing self-diagnosis.In the case of faulty communication between the control unit for trailer recognition and the vehicle electrical system control unit, the rear lights are actuated as a warning signal.J386J387 Door control unitsVehicle self-diagnosis09 – Electronic central electrics 8E0907279B int. load module RDW 0811 Code 101 Dealership No. 680302 - Interrogate fault memory 03 - Final control diagnosis 04 - Basic setting 05 - Erase fault memory 06 - End output 07 - Encoding control unit 08 - Read measured value block 09 - Read individual measured value 10 - Adaption 11 - Log-in procedureJ388Print HelpJ389Measuring equipmentSkipVAS 5051Control unit for vehicle electrical system J519 CAN BUS K wire Central convenience electronics J393 Steering wheel electronics module J453 Control unit for trailer recognition J345RTSSP254_018 Steering column switch module J52757Electrical systemConvenience systemThe convenience system previously used in the Audi A2 is also used in the Audi A4. In the series version, the following additional functions – Door warning lights – Radio remote control and in the optional version, the following functions – Anti-theft alarm with interior monitor and towing protection (new) – Electric sliding/tilting/glass sun roof – Footwell lights – Exit lights – Mirror fold-in function – Mirror memory function are included in the Audi A4. In the basic version without rear electric window lifters, central locking control of the rear doors is assumed by the central convenience electronics.Central convenience unit J393Door control, driver’s side unit J386Door control unit, passenger’s side J387Door control unit, rear left J388 (optional)Door control unit, rear right J389 (optional)SSP254_13258Central convenience electronics (CCE) The following information and functions are processed in the central convenience electronics: Sensors ActuatorsCrash signal (from airbag control unit J234) Handbrake switch F9 Tailgate release – Button for release, tailgate lock cylinder F248 – 3. Remote control button – Switch for tailgate to F206 – Switch for central locking, tailgate F218 Anti-theft alarm (optional) – Contact switch for bonnet F266 – Ultrasonic sensor for anti-theft alarm G209 Aerial for remote control, Central locking and anti-theft alarm in multi-communication bar Reversing lamp M17 When mechanical window lifters fitted in rear – Door contact signal – Locking signal – Safe signal for rear doorsFuel filler flap – Motor for tank cap locking V155 Tailgate – Motor for tailgate release V139 Anti-theft alarm (optional) – Horn for anti-theft alarm H8 (sounder) – Turn signal lights via data bus to vehicle electrical system control unit J519 Interior light control – Dimming of interior lighting – Footwell light switching (optional) – Luggage compartment lamp switching Automatic closing/opening – Window lifters via door control units – Sun roof When mechanical window lifters fitted in rear – Lock rear door lock motors – Safe rear door lock motors – Activation of rear entry lights (optional) – Activation of rear door warning lights Enabling of door control units and sunroof Gateway function for diagnosis – Control unit for vehicle electrical system J519 – Steering column switch module J52759Electrical systemDoor control units The door control units integrated in the window lifter motors process the following signals: Sensors ActuatorsWindow lifter switches Enabling via the CCE Door lock feedback signal – Door contact signal – Locked signal – Safe signal for driver’s door also – Lock cylinder switch unlocking/ locking F241 – Interior central locking switch F59 – Switch for childproof lock E254 (optional) – Central window lifter operation – Mirror adjustment switching E48 – Switch for mirror adjustment E43 – Switch for mirror fold-in function (optional) E263 – Switch for unlocking luggage compartment (USA) E164 – Switch for seat memory, driver’s side (optional) E263 – Switch for interior monitor E183 (optional) – Inclination sensor switch (optional) for front doors also – Mirror release switch (optional) – Sender for mirror position for mirror memory (optional)Door locking and unlocking Safe activation and deactivation of the doors Activation of illumination in the doors – Entry lights (optional) – Door opener illumination (optional) – Door warning lights – Switch illumination for front doors also – – – – Electric mirror adjustment Mirror heating Mirror fold-in function Mirror memoryfor driver’s door also – Control of indicator LED – Inclination sensor LED switched off (optional) – LED, interior monitoring – LED, childproof lock additionally for passenger's door – Mirror for reversing (optional)60Mirror functions The mirror heating is switched on together with the – rear window heating – at an outside temperature of below 20 °C switches on automatically. When the mirror heating is switched on, the heating capacity is 100%. Then the heating is activated intermittently in accordance with the ambient temperature and vehicle speed. The mirror glass is kept at a temperature of around 20 °C.SSP254_126The mirror fold-in function (optional) returns the mirrors to the normal position at a vehicle speed of 15 km/h. The function is disabled at the same time.Passenger’s side mirror Lowering of the mirror (optional) takes place when the reverse gear is engaged. The mirror is returned to its original position by – operating the mirror selector switch, or – when the speed of 15 km/h is exceeded.SSP254_127SSP254_128Diagnostics The adjustment of various settings can be performed via the control unit coding and adaption functions of the convenience system diagnosis. Customer requirements relating to the convenience opening and closing functions can be taken into account via adaption channel 62.61In order to account for the resistance of normal or insulating windows with regard to the excess force limitation function of the electric window lifters, the relevant type of glazing is set in adaption channel 63.Electrical systemAnti-theft alarm with interior monitorDoor lockTSIgnition steering lock DConvenience data busCentral control unit for convenience system J393High and low pitched tones - air horn (sounder) SSP254_133The Audi A4 convenience system is available with – – – – Anti-theft alarm Ultrasonic interior monitor Shattered glass sensor (Avant) Towing protectionDeactivation is performed by – opening the vehicle via the radio remote control or – opening the vehicle via the driver’s door lock cylinder and switching on the ignition within 15 seconds. If this time period is not observed or if the key used is not stored in the immobiliser, the alarm is triggered. Data exchange between the immobiliser in the dash panel insert and the central convenience electronics takes place via the convenience data bus.as optional extras. The anti-theft alarm is only activated when the vehicle is locked via the radio remote control and by closing the driver's door.62An innovation in the anti-theft alarm is that a sounder with an integrated battery is fitted in place of the horn. This enables the alarm to sound even when the power supply has been interrupted.SSP254_134The ultrasonic interior monitor and the towing protection can be switched off from inside the passenger compartment by means of a switch.SSP254_135Diagnostics The angles of the both the longitudinal and transversal inclination of the inclination sensor are displayed in the measured value block.63Electrical systemFunctional mechanism of inclination sender Towing protection is achieved by means of the inclination sender installed in the central convenience electronics. The functional mechanism of the inclination sender is based on the determination of resistance changes relating to the volumetric fluctuation of a viscous electrically conductive fluid. Variously arranged electrodes project into this fluid. Alternating fields are applied to the electrodes of the sender, which is divided into sub-compartments. When a change in position occurs, the distribution of the fluid in the chambers also changes. As the level of the liquid in the sub-compartments changes, the resistance determined for the sub-compartments via the electrodes also changes.SSP254_110 Ceramic housing Sub-compartment Indicator fluidElectrode connectionsElectrodesThe resistance is stored at the moment of activation of the anti-theft alarm. Changes in the position of the inclination sensor caused by one-sided lifting of the vehicle alter the resistance. The alarm is triggered. The angle of inclination can be displayed in the measured value blocks.Operational amplifierSSP254_111 64Radio chorus II, concert II and symphony II In the new Audi A4, the new generation of radios, chorus II, concert II and symphony II are available as options. The following functions have been optimised: – AM has been extended to include long wave. – There are now 12 programmable stations for AM and FM. All three radio versions are compatible with the external CD changer (optional). The optional CD changer is now built into the glove compartment.AIRBAGLOADCOMPAKT AKTAudi cd charger OFF ONDIGITAL AL AUDIOSSP254_106The BOSE sound system can be ordered as an optional extra for all radio systems of the new generation. The connection of the new generation of radios to the data bus information system enables the exchange of large volumes of data with other systems. This makes new functions such as e.g. convenience radio coding possible. Thanks to the convenience radio coding, manual deactivation of the radio anti-theft lock following a loss of the power supply is no longer necessary. A prerequisite is that the radio is built into the same vehicle. Sound quality is enhanced by the installation of a central loudspeaker in the centre of the dash panel as well as a sub-bass speaker under the rear shelf.65Electrical systemRadio chorus II New functions with respect to the predecessor model include: – Skip title function – Scan function – Dolby noise suppression in the cassette player as well as – a sorting function within a radio station family in the convenience radio tuner search function.SSP254_009Radio concert II A single speed CD player is integrated in the concert II radio. The cassette player has been discontinued.SSP254_007Radio concert II and symphony II The improved radio traffic news memory in the Radio concert II and symphony II allows the driver to program the time for starting the two-hour recording of traffic news announcements. Two timers are available, which can be programmed individually. Example: The driver can set the starting time for the recording of radio traffic news announcements for the drive to work in the morning and for the drive back in the evening separately. Radio reception is improved in the concert II and symphony II radios by the use of the Multi Communication Bar (MCB) with integrated aerial diversity. For further information on the aerial module, please refer to 72. In order to improve sound quality, acoustic curves related to vehicle type are stored in the concert II and symphony II radios. The acoustic curves are set in the control unit coding function of the radio systems. In addition, the sound settings for the FM, AM and CD modes are stored separately in the concert II and symphony II radios. Consequently, the various level controls do not require resetting each time the driver changes modes.66Radio symphony II A 6x CD changer as well as a cassette player are integrated