Self Study Programme 609 For internal use onlyAudi A3 ’13Audi Service TrainingThe Audi A3 can look back on a 16-year success story. The first generation of the series, which debuted in 1996 as a three-door, established an entirely new market segment – the premium compact class. In 1999 the five-door hatchback and the sporty Audi S3 completed the family. In total, around 990,000 units were sold. The second generation, launched in 2003, was even more successful, achieving sales of around 1.8 million units. In the emerging competition, the A3 was the dominant force in the premium compact class. The Group has set itself the task of improving the fuel economy of its internal combustion engines, extending its product range to include alternative drive systems such as natural gas engines and electric motors, and equipping as many vehicles as possible with the latest technical innovations. The basis for implementing these objectives is the Modular Transverse Platform (MTP), a standardised architecture on which various vehicle components can be combined in any configuration on modular principles. This broadens the diversity of the model range, resulting in more efficient production, engines and combinations of materials. The Audi A3 ’13 represents the cumulative technological expertise of Audi in a compact format. In its lightweight body, its interior architecture and its user interfaces, this three-door model is once again setting standards in its class. Its engines impress with their efficiency and power, and the range of driver assistance systems and infotainment solutions is unparalleled in the premium compact class.The progressive formal language visualises the sheer passion with which Audi develops and makes cars. Ultra-lightweight design has long been a success formula and a hallmark of the Audi brand. This is by no means confined to a single, specific material. On the contrary, Audi’s motto is: "The right material in the right place for optimal function". True to this maxim, the engineers have developed a multi-material body for the new A3. The lightweight body and downsized engines have had major knock-on effects throughout the vehicle, reducing the weight of many suspension, exhaust and interior components. At launch, Audi will supply the A3 ’13 with one TDI engine and two TFSI engines. The Modular Infotainment Platform (MIB) makes its debut in the Audi A3 ’13 – it represents a big step forward in mobile communication electronics. The Audi A3 ’13 also sets new standards in the premium compact class when it comes to driver assistance systems. The most important of these is Audi adaptive cruise control. In the event of an impending collision, the ACC system warns the driver in progressive stages and,if necessary, can initiate partial braking in order to reduce the car’s speed at impact.609_047The Self Study Programme teaches a basic knowledge of the design and functions of new models, new automotive components or new technologies. It is not a Repair Manual! Figures are given for explanatory purposes only and refer to the data valid at the time of preparation of the SSP. For further information about maintenance and repair work, always refer to the current technical literature.NoteReference2ContentsIntroductionIn brief _______________________________________________________________________________________________________________________________________________________ 4BodyBody structure _______________________________________________________________________________________________________________________________________________ 6 Attachments _________________________________________________________________________________________________________________________________________________ 8 Joining techniques __________________________________________________________________________________________________________________________________________ 8 Panorama tilt sunroof _____________________________________________________________________________________________________________________________________ 10 Bumper system _____________________________________________________________________________________________________________________________________________ 12 Underbody __________________________________________________________________________________________________________________________________________________ 13 Tow bar ______________________________________________________________________________________________________________________________________________________ 13Passive safetyComponents ________________________________________________________________________________________________________________________________________________ 14 System overview ___________________________________________________________________________________________________________________________________________ 15 Airbag systems _____________________________________________________________________________________________________________________________________________ 16 Seat occupancy sensor _____________________________________________________________________________________________________________________________________ 18 Pedestrian protection ______________________________________________________________________________________________________________________________________ 20Active safetyAudi pre sense ______________________________________________________________________________________________________________________________________________ 22EnginesPetrol engines ______________________________________________________________________________________________________________________________________________ 28 Diesel engines ______________________________________________________________________________________________________________________________________________ 34 Fuel system _________________________________________________________________________________________________________________________________________________ 38 Exhaust system _____________________________________________________________________________________________________________________________________________ 39 Engine/gearbox combinations ____________________________________________________________________________________________________________________________ 40Power transmissionOverview ____________________________________________________________________________________________________________________________________________________ 42 5th generation Haldex coupling __________________________________________________________________________________________________________________________ 44 Freewheel mode of dual clutch gearbox 0D9 / 0CW ___________________________________________________________________________________________________ 50 Selector mechanism _______________________________________________________________________________________________________________________________________ 51Suspension systemOverall concept _____________________________________________________________________________________________________________________________________________ 52 Steering system ____________________________________________________________________________________________________________________________________________ 54 Brake system _______________________________________________________________________________________________________________________________________________ 55 adaptive cruise control (ACC) _____________________________________________________________________________________________________________________________ 56 Wheels and tyres ___________________________________________________________________________________________________________________________________________ 57Electrical systemAudi drive select ____________________________________________________________________________________________________________________________________________ 58 Installation locations of control units ___________________________________________________________________________________________________________________ 60 Topology ____________________________________________________________________________________________________________________________________________________ 62Air conditioningIntroduction ________________________________________________________________________________________________________________________________________________ 64 Heater and air conditioner ________________________________________________________________________________________________________________________________ 66 Auxiliary heater ____________________________________________________________________________________________________________________________________________ 67 Connected components ___________________________________________________________________________________________________________________________________ 70InfotainmentOverview of versions _______________________________________________________________________________________________________________________________________ 72 Modular Infotainment Platform (MIP) __________________________________________________________________________________________________________________ 74 Audi connect (market dependent) ________________________________________________________________________________________________________________________ 79 Components in the Audi A3 ’13 __________________________________________________________________________________________________________________________ 80 Universal Mobile Phone Preparation – Audi phone box _________________________________________________________________________________________________ 86ServiceSpecial tools and workshop equipment __________________________________________________________________________________________________________________ 88 Inspection and maintenance ______________________________________________________________________________________________________________________________ 90 Self Study Programmes ___________________________________________________________________________________________________________________________________ 913IntroductionIn brief609_035609_036609_0374609_038Length in mm Width in mm Height in mm Track width, front in mm Track width, rear in mm Wheelbase in mm Trailer load in kg with brake at a gradient of 8 % Kerb weight in kg Max. gross weight in kg4237 1777 1421 1542 1514 2601 18004)Cabin width, front in mm Cabin width, rear in mm Headroom, front in mm Headroom, rear in mm Through-loading width in mm Load sill height in mm Boot capacity in l Tank capacity in l Drag coefficient in cw1464 1411 1020 951 1000 686 365/11005) 50 0,3112804) 1840Width of shoulder room Width of elbow room 3) Maximum headroom 4) with a 2.0l TDI engine developing 110 kW at 320 Nm 5) with the seat back folded down and loaded up to roof level1) 2)All dimensions are given in millimetres and refer to the unladen weight of the vehicle.5BodyBody structureA major factor in achieving the ambitious body weight targets for the Audi A3 ’13 was the systematic application and development of lightweight design. Thanks to Audi ultra-lightweight design technology, the Audi A3 ’13 is much lighter than its predecessor. The following factors were taken into account: • • • • Passive safety Torsional rigidity Vibration comfort AcousticsUltra-high-strength hot-formed componentsUltra-high-strength hot-formed components are used for the first time in the Audi A3 ’13, increasing the stability of the occupant cell without adding weight. The occupant cell is the survival space for the vehicle's occupants.Ultra-high-strength hot-formed components are installed in the following areas:1Side member 2, left/right Upper footwell cross member Lower footwell cross member Inside left/right sill panel Tunnel6Heel section reinforcement Cross member Top left/right A post Rear side member, left/right Inside left/right B post2738495106Key: Ultra-high-strength steels (hot-formed) 12 % Modern high-strength steels 19 % High-strength steel 13 % Soft steel 56 %609_05289 10 74 5 62 13609_0557AttachmentsThe attachments, specifically the doors and the rear hatch, are of lightweight steel construction. For the first time in the third generation of the Audi A3 ’13, aluminium is used in the following components: • Bonnet • Wings A further reduction in weight of more than nine kilogrammes was achieved by using aluminium.Key: Ultra-high-strength steel (hot-formed) Modern high-strength steel High-strength steel Mild steel Sheet aluminium Aluminium sectionJoining techniquesResistance spot welding is the predominant joining method in the body structure of the Audi A3 ’13. Its acknowledged advantages are those of affordability, durability and process reliability. Resistance spot welding is combined with a high-strength bonding process in the body zones where stringent requirements apply to vibration comfort and passive safety. This produces a strong surface attachment to the structural flanges, increasing structural rigidity and significantly reducing the load on highly stressed spot welds.8609_053Resistance spot welding: 76.3 %Plasmatron brazing is used to meet the exacting visual specifications in other outer body areas, producing a seamless joint between the roof and sidewall frame and in the water channel between the rear hatch and sidewall.Plasmatron brazing: 8 %Bonding: 14.6 %MAG welding: 3.1 %609_0549Panorama tilt sunroofThe panorama slide/tilt sunroof is an equipment option for the Audi A3 ’13. It is fitted as an externally guided roof system. This roof is a further development of the well-known Audi A1 panorama sunroof and has been adapted to the Audi A3 ’13 with respective to its design and size. The roof opening is larger than that of an internally guided sunroof and creates a particularly airy and spacious interior feel for the occupants.609_069Thermal insulationThe glass roof panel is tinted and provides additional thermal insulation. Thermal insulation is provided by the following reflective components: • 99 % UV radiation reflection • 92 % heat radiation reflection • 90 % light radiation reflection The panorama slide/tilt sunroof module meets the statutory requirements for anti-pinch protection.609_08310Roof installationThe Audi A3 ’13 panorama slide/tilt sunroof is glued into the roof opening and thus is a major factor contributing to body rigidity.Transverse bonded seam609_122609_070Bonded ring seamComponent overviewGlass panelSlide/tilt mechanismWind deflectorFront trim (plastic)Cover for sliding sunroof motor/ roll-up sunblindSliding sunroof frame (plastic) Roll-up sunblindSliding sunroof motorLifting arm guide frame609_07111Bumper systemFront bumperCharacteristic elements of the vehicle's front end are the one-piece bumper cover and striking single-frame radiator grille. Large air intakes in the front hint at the power of the engines. In addition to existing APS and ACC sensors in the bumper system, the Audi A3 ’13 is equipped with further pedestrian protection sensors. These sensors are located on the back of the front bumper cover.Shock absorberACC radar sensor Impact absorber Bumper cover locking part Radiator grille Front bumper cover609_072Rear bumperThe rear bumper comprises a cover with a welded locking part and a spoiler with integrated diffusor for the exhaust tail pipes. The sensors for the optional Audi side assist system are mounted to the locking part. The rear sensors for the optional parking aid or park assist function are mounted to the spoiler cover. The bumper is attached to the rear end of the body using the locking part. The pre-assembled guiding parts are attached flush with the body side sections.Impact absorber Wiring harness and rear bumper sensors Rear bumper coverBumper cover spoiler609_073 12UnderbodyThe Audi A3 ’13 has an acoustically and aerodynamically highly effective underbody designed to withstand mechanical and thermal stresses. In addition to aerodynamics, attention was paid to sound absorption, body protection and thermal engine management during the development phase. The result is improved airflow around the engine and gearbox capsule, the cross-members and the wheel arches, thus allowing a low drag coefficient (cw) of 0.31 to be achieved.609_082Tow barAs an option, the Audi A3 ’13 can be ordered with a tow bar including a removable ball rod. The ball rod is located beneath the load floor cover in the vehicle's luggage compartment. It is possible to attach and remove the ball rod by hand, but this must be done with care in order to ensure that it is locked securely.Tow bar crossmemberBall rod609_074 13Passive safetyComponentsThe passive occupant and pedestrian protection system in the Audi A3 ’13 comprises the following components and systems: • • • • • • • • • • • • • • Airbag control unit Driver and passenger airbags Front side airbags Head airbags Driver side knee airbag Front airbag crash sensor Crash sensors for side impact detection in the doors Crash sensors for side impact detection in the C posts Crash sensors for pedestrian protection in the front bumper cover Front inertia reel seat belts with electric and pyrotechnic belt tensioners Seat belt warning for all seats Seat belt switches on all seats in the seat belt buckles Seat occupancy sensor in front passenger seat Pedestrian protection trigger609_007Additional equipmentThe vehicle can optionally be equipped with a keyswitch for deactivating the front passenger airbag with accompanying warning lamp. Due to the different statutory provisions and requirements for car makers in the various markets, equipment specifications can vary.Key to figure on page 15: E24 E25 E224 E258 E259 E609 G128 G179 G180 G256 G257 G283 G570 G571 G598 G599 G693 Seat belt switch, driver side Seat belt switch, passenger side Airbag disabling switch, passenger side (optional) Rear seat belt switch, driver side Rear seat belt switch, passenger side Rear central seat belt switch Passenger side seat occupancy sensor Side airbag crash sensor, driver side Side airbag crash sensor, passenger side Rear side airbag crash sensor, driver side (C post) Rear side airbag crash sensor, driver side (C post) Front airbag crash sensor, driver side (front end) Pedestrian protection crash sensor, driver side Pedestrian protection crash sensor, passenger side Pedestrian protection trigger 1 Pedestrian protection trigger 2 Pedestrian protection crash sensor, centre J234 J285 J533 J854 J855 Airbag control unit Control unit in instrument cluster Data bus diagnostic interface (gateway) Front left seat belt tensioner control unit (optional) Front right seat belt tensioner control unit (optional)K19 Seat belt reminder warning lamp K75 Airbag warning lamp K145 Passenger airbag off warning lamp (PASSENGER AIRBAG OFF) (optional) N95 N131 N153 N154 N199 N200 N251 N252 N295 T16 Driver side airbag igniter Passenger side airbag igniter 1 Seat belt tensioner igniter 1, driver side Seat belt tensioner igniter 1, passenger side Side airbag igniter, driver side Side airbag igniter, passenger side Head airbag igniter, driver side Head airbag igniter, passenger side Knee airbag igniter, driver side 16 pin connector, diagnostic portNote The diagrams in the chapter entitled "Passive occupant safety" are schematic diagrams and serve to provide a better understanding.14System overviewThe system overview shows by way of example the equipment options available for a German-spec model.Key: Powertrain CAN bus Convenience CAN bus Diagnostics CAN bus Input signal Output signal609_00115Airbag systemsPassenger airbagThe Audi A3 ’13 is equipped with a single-stage hybrid gas generator on the passenger side. For the first time in an Audi, a canistertype gas generator is used on the passenger side in place of a tubular gas generator. The advantage of this is that the passenger airbag module of the Audi A3 ’13 is about 25% lighter than in the Audi A3 ’04.609_012Airbag connectorGas generatorHousingThe passenger side airbag igniter N131 ignited by the airbag control unit J234 (igniting resistance wire including a small amount of pyrotechnics) punctures rupture disc 1. This ignites the priming charge, which in turn ignites the actual propellant charge. Rupture disc 2 ruptures due to the rise in pressure. The mixture of cold gas and reaction gas – resulting from combustion of the pyrotechnics – escapes through the metal filter and flows through the outlets and into the folded airbag.The airbag inflates inside the dash panel. If the pressure on the perforation in the dash panel is high enough, the perforation breaks open and the airbag is fully inflated inside the occupant cell.Rupture disc 2Metal filter Outlets Cold gasPriming charge Rupture disc 1 Propellant chargeIgniter609_01316New connector generationIn comparison to its predecessor, the additional ground line on the passenger airbag has been integrated into the passenger airbag connector in the Audi A3 ’13. This ground line is designed to protect the passenger airbag pyrotechnics against electrostatic discharge. After contacting the connector, the ground cable connects the gas generator housing to the body in an electrically conductive manner. The airbag connector is encoded mechanically.CoverLocking deviceContactMechanically encoded housingDriver side knee airbagThe Audi A3 ’13 is equipped with a knee airbag on the driver's side. The knee airbag is designed as a tubular-type cold gas generator.609_014The knee airbag is connected to the body in an electrically conductive manner by the bracket. To ensure electrical conductivity, there must be sufficient contact between the mount and the body. Please pay attention to the workshop manual.Attachment points in vehicleKnee airbag igniter, driver side N295TabsKnee airbag609_015The knee airbag igniter, driver side N295 activated by the airbag control unit J234 (igniting resistance wire including a small amount of pyrotechnics) punctures rupture disc 1. The cold gas compressed under high pressure in the gas cylinder escapes through the outlets and into the folded airbag. The knee airbag, which has a capacity of approx. 14 litres, inflates.It ensures that the knee and the lower leg of the driver are better protected.Outlets609_016Cold gasCompressed gas cylinderRupture disc 1Knee airbag igniter, driver side N29517Seat occupancy sensorThe Audi A3 ’13 is equipped with a passenger side seat occupany sensor G128. The passenger side seat occupany sensor is a component of the seat belt reminder system. The sensor consists of two plastic films which are bonded together. Electrically conductive circuit tracks and contact faces are printed onto the insides of the films. The plastic films in the area of the contact sensors are kept apart using spacer film and are not bonded. Consequently, there is no contact between the contact films in the area of the contact sensors in the rest state. If weight is now placed on the seat occupany sensor, the films in the proximity of the contact sensors are pressed together, reducing the total resistance to less than 120 ohms. At least one contact sensor on each side must be compressed in order that the seat position sensor detects occupancy. If the passenger seat is unoccupied, the seat occupany sensor has a high resistance (approx. 470 ohms). For the first time in an Audi, the seat occupany sensor of the Audi A3 ’13 is mounted directly on the seat shell and NOT on the seat cushion. The sensor is fitted with round and oblong-hole clips for exact positioning. The clips are premounted to the sensor. In addition, the sensor is marked TOP and FRONT.609_022Passenger side seat occupancy sensor G128Connector plugContact sensorContact sensorBonded plastic filmsContact sensorContact sensorContact sensorContact sensor609_018Round clipOblong-hole clip18Front seat belt tensionerIn combination with pre sense basic front automatic seat belt retractors, the Audi A3 ’13 is equipped with reversible seat belt tensioners with electric motors in addition to the pyrotechnic belt tensioners. The reversible seat belt tensioners together with the front left and right seat belt tensioner control units (J854 and J855 respectively) are connected to the airbag control unit J234 as LIN control units. When Audi pre sense basic detects specific driving situations, signals are sent to the data bus. The airbag control unit evaluates the signals and, if necessary, instructs the seat belt tensioner control unit to partially or fully tension the seat belts via an electric motor. For further information on Audi pre sense, refer to the chapter on Active safety, page 22 ff. The automatic seat belt retractors use rack-type pyrotechnic belt tensioners. If an automatic seat belt retractor with seat belt tensioner control unit is replaced, the basic setting procedure must be performed using the "Guided Fault Finding" function.Seat belt tensioner control unitReversible belt tensioner with electric motorPyrotechnic seat belt tensioner609_080Side airbag crash sensorThe side airbag crash sensors for the driver and passenger sides (G179 and G180) are capacitive pressure sensors. The pressure sensors have a new mounting concept and are no longer bolted. The pressure sensors are inserted into the sheet metal of the driver and passenger door and fastened by twisting. The seals seal off the system. The view shows the crash sensor locked in place, but without the door panel.FasteningPlug connectionSealTwisting tool609_081Reference For information on removing and installing the side airbag crash sensor, refer to the workshop manual.19Pedestrian protectionThe Audi A3 ’13 is equipped with a system which can reduce the extent of head injuries sustainable by pedestrians in the event of a head-on collision with an Audi A3 ’13. For this purpose, the bonnet is "displaced" to increase the distance between the bonnet and components in the engine bay and thereby create an additional "crumple zone".G570 G693 G571609_006Pedestrian protection crash sensorTo enable the Audi A3 ’13 to detect a collision with a pedestrian, it is equipped with additional crash sensors: • Driver side pedestrian protection crash sensor G570 • Passenger side pedestrian protection crash sensor G571 • Pedestrian protection crash sensor G693 These sensors are located on the back of the bumper cover. They are acceleration sensors.609_002Pedestrian protection triggerThe pedestrian protection system triggers are pyrotechnic components comprising an igniter unit and cylinders with pistons. • Pedestrian protection trigger 1 G598 • Pedestrian protection trigger 2 G599 The same safety precautions apply as for airbags.Igniter unitCylinder with piston609_003Note The system is non-reversible and must be repaired immediately. After the bonnet has been displaced back, the vehicle can still be driven to the nearest authorised repairer.20FunctionIn the event of a collision with a pedestrian at a speed of between approximately 25 and 55 kph, the airbag control unit J234 activates both pedestrian protection triggers (G598 and G599). The propellant charges are ignited at the same time, and the developing gas pressure displaces the pistons in the pedestrian protection cylinders. The pistons are attached excentrically to the hooks, with the result that the longitudinal movement of the piston causes the hooks to rotate. The hooks rotate away from the counter bearings and the pistons extend. Due to the kinematics of the bonnet hinges, the bonnet is displaced approximately 20 mm backwards and approximately 52 mm upwards at the back.Bonnet hinge in rest positionBonnet hinge deployedHinge attachment to bonnetHookPedestrian protection trigger G598, G599609_008Hinge attachment to wing stay609_009Fault messageFaults in the system are indicated by the airbag warning lamp K75 in the instrument cluster (control unit in instrument cluster J285). In addition, the instrument cluster displays a warning triangle and the following text for six seconds after ignition "on": „Safety system: malfunction! See owner's manual“. The airbag control unit J234 continuously monitors the pedestrian protection system for proper functioning. Irregularities in the system are registered as diagnostic trouble codes in the airbag control unit. For information about repair operations on the pedestrian protection triggers, refer to "External body repairs" in ELSA. The repair operations on the pedestrian protection crash sensors are described in "Internal body repairs". A deployed system is indicated in the instrument cluster in much the same way as a fault.Open deployed bonnet The bonnet can only be opened in the deployed state if it has been displaced back. This is done as follows: on the left and right hand sides of the vehicle, push down on the bonnet with both hands at the hinge while simultaneously pushing forward (as shown) until the bonnet locks in its original position.609_010Reference Please follow the instructions given in the workshop manual.21Active safetyAudi pre senseAudi pre sense is able to detect critical driving situations, and initiates measures to prepare the vehicle and occupants for a potential impending collision. This is made possible by networking the various in-vehicle systems. The systems send data continuously to the data bus. Other control units are able to evaluate this information and take appropriate action. Customers can order the Audi A3 ´13 with the optional Audi pre sense basic and/or Audi pre sense front system. Please note that Audi pre sense cannot prevent collisions. It serves only to assist the driver and reduce the severity of the collision.Audi pre sense basicLongitudinal dynamics function If the vehicle is moving forward at a speed of over 30 kph (reverse is not engaged) and the driver executes a "hazard braking manoeuvre" (whereby the brake pressure must reach a defined level), the reversible seat belt tensioners are partially tensioned under electrical power. If ESP (Electronic Stabilisation Program) is set to "Sport" or "Off" with the TCS/ESP button E256 or if Audi drive select is set to "dynamic", the seat belts are not partially tensioned.Drive profile selection switch module E592TCS/ESP button E256Audi drive selectHandbookefficiency comfort auto dynamicindividual609_075Car SystemsSet individual609_076Emergency braking function During an "emergency braking" manoeuvre (brake pressure is at or exceeds a defined value for a defined period of time), the reversible seat belt tensioners are fully tensioned electrically. The airbag control unit J234 evaluates the signals which the ABS control unit J104 transfers to the data bus. It instructs the seat belt tensioner control units, J854 and J855, to fully tension the seat belts, both electrically and reversibly. Depending on the situation, the ABS control unit J104 can instruct the hazard warning flashers to be activated.22Transverse dynamics function If the Audi A3 ´13 oversteers or understeers, the ESP system tries to stabilise the vehicle. If the vehicle becomes unstable because certain physical limits have been exceeded, the airbag control unit J234 initiates a partial tensioning of the electrically reversible seat belt tensioners. If the vehicle can no longer be stabilised, the electrically reversible seat belt tensioners are fully tensioned. At the same time, the side windows and the tilt/slide sunroof (if fitted) begin to close. • If ESP is set to "Sport" or "Off" or if Audi drive select is set to "dynamic", the seat belts are not partially tensioned. • If ESP is set to "Sport" mode or "Off", the seat belts are fully tensioned only if the driver actively applies the brakes.Crash function in the low speed range If the airbag control unit J234 detects a head-on collision with low vehicle deceleration (no airbag deployment), it decides whether or not to fully tension the seat belts based on a situation-specific control unit algorithm. It does not take any other precautions, such as turning on the hazard warning flashers, or closing a window or sliding sunroof. System characteristics of Audi pre sense basic: • If a seat belt is not being worn or if the passenger airbag is set to "Off", the reversible seat belt tensioner is not activated. • The belt tensioner control units (J854 and J855 respectively) are connected to the airbag control unit as LIN control units. • The forward displacement of the front occupants can be reduced by more than 100 mm by tensioning the seat belts.Audi pre sense frontThe optional Audi pre sense front system also comes with Audi adaptive cruise control (ACC). The ACC radar sensor which is integrated in the ACC control unit J428 monitors the traffic ahead of the vehicle and continuously measures the distance to a vehicle driving ahead. The ACC control unit evaluates the data and transfers relevant signals to the data bus. Other bus users receive the signals. The ACC control unit utilises these signals to initiates different actions via the control unit in the instrument cluster and the ESP control unit, if necessary.Front camera for driver assistance systemsAudi pre sense front is active even if the ACC system is not activated. Audi pre sense front has the following functions:ADriver information when following a vehicle ahead at a critical distance in certain situations.BIn the event of an impending collision with a moving or stopped vehicle, the driver is warned and assistance is provided by automatic braking or by increasing the braking force applied by the driver, thereby gaining reaction time and reducing speed.609_077Radar sensorCFull deceleration is provided in the event of an impending collision with a moving, stopped or stationary vehicle at a speed of less than 30 kph.23Function AThe driver is warned visually if approaching another vehicle ahead and subsequently when following this vehicle at a critical distance and at a synchronised speed. The critical distance is defined as the distance at which a collision is likely to occur in the event of sudden heavy braking of a vehicle driving ahead, even if the driver of the following vehicle reacts quickly.Approaching vehicle driving aheadSpeed synchronisationFollowing at a critical distance including visual distance warning (ACC warning lamp)Collision609_061Function BWhen the vehicle approaches a moving vehicle, the control unit in the instrument cluster J285 warns the driver visually and audibly if certain defined limits are exceeded. These warnings are issued within a certain period of time prior to the last braking opportunity for collision avoidance before the actual collision. The timing of warnings depends on the driver's degree of activity. Depending on steering, pedal and turn signal inputs, the system classifies the driver as active or inactive and, consequently, as attentive or unattentive. If the driver is attentive, the warning will be issued later than for an unattentive driver. At the same time, the ABS control unit J104 prefills the brake system and modifies the deployment algorithms for Hydraulic Brake Assist. This means that Hydraulic Brake Assist begins to build up brake pressure even at low brake pedal actuation speeds. If the driver does not respond to the warnings or, for example, eases off the accelerator, the ABS control unit J104 performs a warning braking application. The warning braking application is a very brief but easily noticeable braking operation and does not serve to slow the vehicle down. It alerts drivers to the traffic situation and indicates to drivers that they must react immediately in order to avoid an impending collision. Depending on how attentive the system evaluates the driver to be, the warning braking application occurs within a specific period of time ahead of the last opportunity for braking and evasive action in order to avoid a collision. If the driver still fails to react or eases off the accelerator, the vehicle is braked by partial braking operation I, which applies up to 35 % of maximum braking force. If the vehicle is fitted with a front camera for driver assistance systems R242 and this camera also detects the obstacle, the braking force is increased to up to 60 % of the maximum by partial braking operation II. If the driver applies the brakes, a target braking maneouvre can be performed in all phases described above (prefill brake system, reconfiguration of Hydraulic Brake Assist, driver warning, warning braking application, partial braking operations I and II). During the target braking manoeuvre, the Audi pre sense front system calculates whether the driver is applying sufficient braking force to be able to avoid a collision. If this is not the case, the required brake pressure is increased depending on the situation.Prefill brake system Hydraulic Brake Assist reacts with higher sensitivityDriver warning visual, audible (forward collision warning)Warning brakingPartial braking operation I or partial braking operation II (on models with front camera for driver assistance systems)CollisionTarget braking609_063 24Function CAudi pre sense front also includes a function for "full deceleration at speeds from 0 to 30 kph". If the ACC control unit detects an impending collision when the vehicle is travelling at a speed of less than 30 kph, the ABS control unit J104 prefills the brake system. The deployment algorithms for Hydraulic Brake Assist are adjusted at the same time. Hydraulic Brake Assist thus begins to build up brake pressure even at low brake pedal actuation speeds. If the driver fails to brake or does not apply sufficient braking force in a critical situation, the ABS control unit J104 executes a braking maneouvre and applies near-maximum braking if necessary. Before deploying, the vehicle briefly alerts the driver, both audibly and visually, to the fact that it is about to brake independently or provide additional braking. If the Audi A3 ’13 has independently braked to a standstill without any driver intervention, three more audible signals are given. These signals alert drivers to the fact that they must actively take over the vehicle (e.g. by braking). If the driver fails to take over the vehicle, e.g. in a model with automatic transmission, the system will release the brake and the vehicle will begin to roll.Prefill brake system Hydraulic Brake Assists reacts with higher sensitivityFull deceleration with visual and audible driving warning prior to interventionCollision609_064System characteristics with respect to "full deceleration at speed of less than 30 kph" • The driver is not given advance warning. • The system reacts to crossing or oncoming vehicles and objects with low radar scatter (e.g. pedestrians). • The system reacts to vehicles which are travelling in the same direction, have stopped or are stationary.Driver prioritisation over system If the driver clearly takes evasive action, accelerates or brakes during the individual phases of Audi pre sense front (functions A to C), the action momentarily being taken by Audi pre sense front (e.g. partial braking operation I) will be suppressed or cancelled. If the obstacles is no longer relevant after evasive action has been taken, Audi pre sense front will cease to provide assistance in this case.25Settings and displaysThere are two options for deactivating Audi pre sense in the MMI. • Option 1: Prewarning off – the audible and visual warnings (distance and forward collision warnings) are deactivated. • Option 2: System off – the audible and visual warnings (distance and forward collision warnings), warning braking, partial and target braking and the "full deceleration at speeds of below 30 kph" functions are deactivated. The functions remain deactivated until they are reactivated in the MMI.Car Systems Car Audi pre sense System Early warning HandbookBoth versions of Audi pre sense are activated.609_078A deactivated Audi pre sense system is temporarily indicated by the following text whenever the control unit in instrument cluster J285 is switched on: "Audi pre sense: off". This alerts the driver (e.g. after stopping for a rest) to the fact that the system is switched off. If only the prewarning has been deactivated, no text message is displayed in the instrument cluster.Audi pre sense: offD4+9.5°C609_079If ESP (Electronic Stabilisation Program) is set to "Sport" or "Off" with the TCS/ESP button E256, then the audible and visual warnings, the warning braking, the partial and target braking, and the "full deceleration at speeds of below 30 kph" functions of Audi pre sense will also be deactivated.Audi pre sense remains deactivated until: • ESP is reactivated with the TCS/ESP button E256. • the ignition is turned off and on again, thereby reactivating ESP. • ACC is activated, since this would result in automatic activation of ESP. If ESP (Electronic Stabilisation Program) is set to "Sport" or "Off" with the TCS/ESP button E256, the following text is temporarily displayed on the control unit in the instrument cluster J285: "Audi pre sense: off".Reference For further information on ACC, refer to Self Study Programme 612 "Audi A3 ’13 Suspension". For further information on the front camera for driver assistance systems R242, refer to Self Study Programme 611 "Audi A3 ´13 Vehicle Electronics and Driver Assistance Systems".26Data bus overviewThe overview shows by way of example some of the information which is exchanged via data bus.ABS control unit J104 Prefill brake system ← E Warning braking ← E Partial braking operations I and II ← E Target braking ← E Driving speed → A Wheel speed FR → A Wheel speed FL → A Wheel speed RR → A Wheel speed RL → A Brake pressure → A TCS / ESP status → A Activate hazard warning flashers → A Longitudinal acceleration → A Transverse acceleration → A Rotation about vertical axis → A ACC control unit J428 Prefill brake system → A Warning braking → A Partial braking operations I and II → A Target braking → A Audible and visual warnings → A Display "Audi pre sense" system malfunction → A Steering angle ← E TCS / ESP status ← E Accelerator position ← E Brake pressure ← E Wheel speed FR ← E Wheel speed FL ← E Wheel speed RR ← E Wheel speed RL ← EOnboard power supply control unit J519 Reversing light switch status → A Close sliding sunroof ← E Close sliding sunroof → A (to LIN user sliding sunroof control unit J245)Sliding sunroof control unit J245 Close sliding sunroof ← E (LIN user of onboard power supply control unit J519)Control unit in dash panel insert J285 Audible and visual warnings ← E Display "Audi pre sense" system malfunction ← EPower steering control unit J500 Steering angle → ASteering column electronics control unit J527 Information electronics control unit 1 J794 Audi drive select set-up → A Cruise control system status → AAirbag control unit J234 Seat belt buckle status → A Passenger airbag status → A Close side windows → A Close tilt/slide sunroof → A Electrical partial tensioning → A (to LIN users front left and right seat belt tensioner control units, J854 and J855 respectively) Electrical full tensioning → A (to LIN users front right and left seat belt tensioner control units, J855 and J854 respectively) Seat belt tensioning status → A Wheel speed FR ← E Wheel speed FL ← E Wheel speed RR ← E Wheel speed RL ← E Longitudinal acceleration ← E Transverse acceleration ← E Rotation about vertical axis ← E Vehicle speed ← E Brake pressure ← E TCS / ESP status ← E Accelerator position ← E Audi drive select set-up ← E Reversing light switch setting ← E Steering angle ← EEngine control unit J623 Accelerator position → ADoor control units J386, J387, J388, J389 Close side windows ← EFront left belt tensioner control units J854 (LIN user of airbag control unit J234) Electrical partial tensioning ← E Electrical full tensioning ← EFront right belt tensioner control units J855 (LIN user of airbag control unit J234) Electrical partial tensioning ← E Electrical full tensioning ← EKey:Data bus in general LIN bus← E → AData is received (input) Data is sent (output)609_06227EnginesPetrol engines1.4l TFSI engine Technical featuresExhaust manifold with turbocharger and catalytic converter609_166Auxiliary unit and timing driveOil sump module with auxiliary unit mount609_170609_169 28Cylinder head cover with integrated valvegear module609_167Intake manifold with integrated charge air cooler609_155 609_168291.8l TFSI engine Technical featuresCylinder head with Integrated Exhaust Manifold (IEM)Optimised thermal management (rotary valve)30Combined FSI/MPI injectionFriction optimisation and lightweight design609_15631SpecificationsTorque-power curve1.4l TFSI engine with engine code CMBA Power in kW Torque in NmEngine speed [rpm]609_058Engine code Type Displacement in cm3CMBA Four-cylinder inline engine 1395 90 (122) at 5000 – 6000 200 at 1400 – 4000 4 74.5 80 10.5 : 1 Bosch MED 17.05.21 Premium unleaded 95 RON EU 5 plus 120Power output in kW (hp) at rpm Torque in Nm at rpm Number of valves per cylinder Bore in mm Stroke in mm Compression ratio Engine management system Fuel Emissions standard CO2 emission in g/km321.8l TFSI engine with engine code CJSA Power in kW Torque in NmEngine speed [rpm]609_057Engine code Type Displacement in cm3CJSA Four-cylinder inline engine 1798 132 (180) at 1250 – 6200 250 at 1250 – 5000 4 82.5 84.1 9.6 : 1 Simos 12 Premium unleaded 95 RON EU 5 130Power output in kW (hp) at rpm Torque in Nm at rpm Number of valves per cylinder Bore in mm Stroke in mm Compression ratio Engine management system Fuel Emissions standard CO2 emission in g/km33Diesel engines1.6l / 2.0l TDI engine Technical featuresCylinder block with integrated balancer shafts (2.0l TDI engine only)609_041Oxidising catalytic converter and diesel particulate filter609_042Cylinder head with variable valve timing (engines conforming to EU6 emissions standard)609_04334Oil pump with integral vacuum pump609_044Active coolant pump609_045Intake manifold module with integrated charge air cooler609_017609_04635SpecificationsTorque/power curve of 1.6l TDI enginePower output in kW Torque in NmEngine speed [rpm]609_048Engine code Type Displacement in cm Stroke in mm Bore in mm Cylinder spacing in mm Number of valves per cylinder Firing order Compression ratio Power output in kW at rpm Torque in Nm at rpm Fuel Engine management system Maximum injection pressure in bar Emissions standard CO2 emission in g/km3CLHA Four-cylinder inline engine 1598 80.5 79.5 88.0 4 1–3–4–2 16.2 : 1 77 at 3000 – 4000 250 at 1500 – 2750 Diesel to EN 590 Bosch EDC 17 1800 with solenoid valve injector CRI2-18 EU5 99Reference For further information about the design and operation of the 1.6l/2.0l TDI engine, refer to Self-Study Programme 608 "Audi 1.6l/2.0l TDI Engines".36Torque/power curve of 2.0l TDI engineEngine with engine codes CRLB and CRBC Power output in kW Torque in Nm (CRLB) Torque in Nm (deviation from CRBC) Engine with engine code CUPA Power output in kW Torque in NmEngine speed [rpm]609_049Engine code Type Displacement in cm Stroke in mm Bore in mm Cylinder spacing in mm Number of valves per cylinder Firing order Compression ratio Power output in kW at rpm Torque in Nm at rpm Fuel Engine management system Maximum injection pressure in bar Emissions standard CO2 emission in g/km3CRBC Four-cylinder inline engine 1968 95.5 81.0 88.0 4 1–3–4–2 16.2 : 1 110 at 3500 – 4000 320 at 1750 – 3000 Diesel to EN 590 Bosch EDC 17 1800 with solenoid valve injector CRI2–18 EU5 106CRLB Four-cylinder inline engine 1968 95.5 81.0 88.0 4 1–3–4–2 16.2 : 1 110 at 3500 — 4000 340 at 1750 – 3000 Diesel to EN 590 Bosch EDC 17 2000 with solenoid valve injector CRI2-20 EU6 -1)CUPA Four-cylinder inline engine 1968 95.5 81.0 88.0 4 1–3–4–2 15.8 : 1 135 at 3500 — 4000 380 at 1750 – 3250 Diesel to EN 590 Bosch EDC 17 2000 with solenoid valve injector CRI2-20 EU5 -1)1)Data was unavailable at editorial deadline.37Fuel systemVarious fuel systems are used in the Audi A3 ’13. Various factors dictate which system is fitted in the vehicle: • • • • Engine type Auxiliary heater quattro or front wheel drive Climate zone of marketFront wheel drive models1.4l TFSI engine 2.0l TDI engineFloat-type vent valve (roll-over function)Float-type vent valve (roll-over function)Fuel pump control unit J538 Tank ventTank ventFuel delivery unit and fuel gauge sender609_023Fuel delivery unit and fuel gauge sender609_024quattro modelsSaddle-type fuel tanks are used in all-wheel-drive models.1.8l TFSI engine2.0l TDI engineFuel pump control unit J538Float-type vent valve (roll-over function)Fuel pump control unit J538Float-type vent valve (roll-over function)Main chamberLever-type sender 2 Fuel delivery unit and fuel gauge senderSecondary chamberMain chamberSecondary chamber Fuel delivery unit and fuel gauge senderLever-type sender 2609_025 38609_177Exhaust system1.4l TFSI engineClose-coupled main catalytic converterCentre silencerRear silencer1.8l TFSI engineClose-coupled main catalytic converterCentre silencer609_0262.0l TDI engineOxidising catalytic converterDiesel particulate filter Rear silencer609_175Exhaust valve control unit J883Rear silencer609_034 39Engine/gearbox combinationsPetrol engines1.2l TFSI engine1)0AH0AJ0CW1.4l TFSI engine0AJ02S0CW1.8l TFSI engine02S0CW0D92.0l TFSI engine1)0FB1)0D9Engine will be introduced at a later date.40Diesel engines1.6l TDI engine02S0CW2.0l TDI engine02Q0D9Gearbox designations:0AH 0AJ 02S 02Q 0FB 0CW 0D9 (MQ200_5F) (MQ200_6F) (MQ250_6F) (MQ350_6F) (MQ350_6A) (DQ200_7F) (DQ250_6A)Breakdown of manufacturer designation: e.g. MQ350-6FM D Q 350 6 F A Manual gearbox Dual clutch gearbox Transverse installation Nominal torque capacity Number of gears Front wheel drive All-wheel drive (quattro)41Power transmissionOverviewThe power transmission system in the Audi A3 ’13 is based on proven technology. The manual gearbox and the dual clutch gearbox are known from the predecessor model. The installation position was adapted in all gearboxes in the course of implementing the Modular Transverse Module, MQB for short. If the vehicle is equipped with Audi drive select and efficiency mode is selected, the dual clutch gearboxes assist this program in selector lever position D by activating the Freewheel mode. Refer to page 50 for more information. The dual clutch gearboxes also assist the start-stop system on a software basis and participate in the immobiliser system for the first time in this class of vehicle. The 5th generation Haldex coupling and the selector mechanism are new Audi technology. Installation location of gearbox The installation position of the gearbox has been adopted to the modular transverse module by modifying the gearbox flanges and the gearbox mounting points. To differentiate the modified gearboxes from the previous gearboxes, the gearbox families have in some cases been renamed. Here is an example: The original 6-speed dual clutch gearbox 02E now has the designation 0D9. The 0D9 gearbox is inclined 12° further back than the 02E.Rear axle drive 0CQFinal drive Rear axle drive ventHaldex coupling ventAll-wheel drive control unit J492Haldex coupling pump V181Haldex coupling609_129 42Innovative thermal management for 0D9 gearboxThe 0D9 dual clutch gearbox is at present the only gearbox of the Audi A3 ’13 whose heat balance is integrated in the innovative thermal management system of the 1.8l TFSI engine. The gearbox cooling circuit is initially open during the starting phase of the cold engine. The gearbox coolant valve N488 is energised for this purpose. The engine control unit switches the valve to ground. If there is enough heat available for the engine and for heating the cabin to the temperature requested by the customer, valve N488 is deenergised. The cooling circuit is now closed and the ATF is heated to operating temperature by the heated engine coolant. The ATF temperature signal is transferred from the gearbox to the engine control unit by the powertrain CAN bus. If the ATF has reached operating temperature, valve N488 is re-energised and the cooling circuit is opened. If the ATF temperature exceeds a permissible value, valve N488 is deenergised again. The cooling circuit is closed. Since the engine coolant temperature is kept below the maximum permissible ATF temperature in this case, the ATF is cooled by the engine coolant. For further information, refer to SSP 486, page 28 ff.Gearbox coolant valve N488: − Activated and diagnosed by the engine control unit J623. − Energised: valve closed, open coolant circuit − Deenergised: valve open, closed cooling circuit12VCoolant feed Coolant return609_130Selector mechanism with emergency release. For further information, refer to page 51.12°Selector lever cable for actuating the parking lock0D9 gearbox609_131Note The processes of the innovative thermal management system described on this page, refer to the 1.8l TFSI engine available at market launch. Engine types due out at a later date and deviating country-spec versions (hot climate/cold climate) are not considered.435th generation Haldex couplingComponent overviewThe control logic in the various driving situations was adopted from the 4th generation Haldex coupling (refer to Self Study Programme 414). The most notable feature of the 5th generation Haldex coupling is a new pressure control system. The hydraulic pressure required for the Haldex coupling is produced by a pump with centrifugal governor. Thanks to this technology, the new Haldex coupling is 1.7 kg lighter than the 4th generation Haldex coupling. An electric motor drives the axial piston pump. The six axial pistons are pushed against an inclined thrust plate. When the pump cylinder rotates, the pistons execute an axial stroke and thus convey the Haldex oil to the pressure side of the pump.Axial needle bearingClutch cage Thrust plateThrust plateClutch plate assemblyAxial needle bearingAxial piston pump with integrated centrifugal governorCentrifugal lever Pressure sideWorking piston with sealsHaldex coupling pump V181Axial pistonThrust plate Haldex coupling pump motor shaft V181 Suction sideCentrifugal force control valvePump sump609_132Pump cylinder44All-wheel drive control unit J492 The all-wheel drive control unit J492 exhanges information via the suspension CAN bus. The driving dynamics software computes the required clutch pressure according to the driving situation. The characteristic curves stored in the control unit are used to determine the pump output which generates the required hydraulic pressure in the working piston cylinder. To control pump output, the pump motor is supplied with a pulse width modulated voltage of 12V and the current input is measured. The hydraulic pressure is determined as a function of current input based on the characteristic curves. If a higher pressure is required, pump output is increased by pulse width modulation of the voltage. Motor engine, pressure and current input increase. To reduce the pressure in the working piston cylinder, pump output is decreased. Motor engine, pressure and current input decrease. A sufficient supply of energy is ensured by the terminal 30 power supply, which is protected by a 15 A fuse.Pressure relief valve The valve ball is pushed down into the valve seat by a steel spring. At a hydraulic pressure of 44 bar, the spring force is no longer sufficient and the valve ball unblocks the valve cross-section. The Haldex oil is displaced to the suction side of the axial piston pump.609_133Needle bearing Drive hub2-way connectorAll-wheel drive control unit J492 8-way connectorOil sleeveHousingPressure relief valveBall bearing Snap ring Ring sealO-ringFlange/prop shaftFlanged nut609_13445Oil supply / hydraulic diagramThe axial piston pump with integrated centrifugal governor is driven by the motor shaft of Haldex coupling pump V181. The centifugal force acting on the centifugal levers of the controller increases with axial piston pump speed. The valve balls of the centifugal force control valves are thereby pushed down into the valve seat more firmly. This increases the pressure maintained by the valves. With the aid of this technology, the system achieves outstanding pressure increase and reduction times. The hydraulic pressure supply of the working piston is controlled by varying the speed of the motor of the Haldex coupling pump V181. If the speed of the motor increases, thereby increasing the pressure supplied to the working piston, the working piston applies more pressure to the clutch plate assembly allowing more torque to be transmitted. If the speed of the motor decreases, thereby reducing the pressure supplied to the working piston, less torque can be transmitted.Working pistonPressure relief valveClutch cageHaldex coupling pump V181Pressurised oil supply to the working pistonPump sumpThrust plate Axial piston pump with integral centrifugal governorCentrifugal force control valveCentrifugal lever609_13546Low pump motor speed There is still no pressure build-up inside the working piston's cylinder. Due to the low speed of the pump motor, the centrifugal levers do not apply pressure to the valve balls. The pumped oil flows back into the pump sump through the centrifugal force control valves of the centrifugal governor.Colour key:Clutch plate assemblyVacuum Unpressurised Oil overflowp 44 barWorking pistonCentrifugal lever Centrifugal forcePressure relief valveCentrifugal force control valveCentrifugal governor and direction of rotation Centrifugal lever mount Haldex coupling pump V181Pump sump609_019Pressure build-up due to increased pump motor speed Pressure builds up inside the cylinder of the working piston. The centrifugal levers now apply pressure to the valve balls and close the gap. The rising pressure pushes the valve balls back slightly, bringing the centrifugal force and the hydraulic force into equilibrium. The pressure inside the working piston, and hence the amount of torque which can be transmitted, rises with increasing motor speed.Colour key: Vacuum Unpressurised Pressure inside working piston cylinderp 44 barThe valve ball is pushed more firmly into the valve seat by the increased speed of the centrifugal governor.Centrifugal governor with increased speed609_02147Overspeeding of pump motor The centrifugal levers apply pressure to the valve balls to such an extent that the pressure inside the working piston cylinder rises to an unacceptable level. When the pressure exceeds 44 bar, the pressure relief valve opens and limits the system pressure.Colour key: Vacuum Unpressurised Excess pressure inside working piston cylinderp  44 bar Pressure relief valve opensOverspeeding centrifugal governor609_020Pressure reduction due to decreased pump motor speed The centrifugal levers exert less pressure on the valve balls. The pressure is relieved through the open valve gap until the centrifugal force and the hydraulic force are again in equilibrium. Colour key: Vacuum Unpressurised Controlled pressure inside working piston cylinderp 44 barPressure is relievedCentrifugal governor with reduced speed609_050 48Function diagramJ4921212345678J492: V181:All-wheel drive control unit Haldex coupling pumpTerm. 31 Term. 30 Term. 15 V181 Suspension CAN bus, high Suspension CAN bus, low609_136The all-wheel drive control unit J492 communicates with the ABS control unit J104 and the power steering control unit via the suspension CAN bus.It communicates with the dual clutch gearbox mechatronics J743, the engine control unit J623 and the control unit in dash panel insert J285 via the data bus diagnostic interface J533.ServiceThe all-wheel drive control unit J492, the Haldex coupling pump and the flange/prop shaft are replaceable. The seals for the housing, drive hub and pump are also replaceable.All-wheel drive control unit J492Haldex oil filler and inspection screwFlange/prop shaftHaldex oil drain screwAxle oil filler and inspection screw Axle oil drain screwHaldex coupling pump V181 Oil bleed port for double shaft oil seal609_137Change intervalsThe Haldex oil must be changed every 3 years, regardless of mileage. The axle oil is not subject to a change interval.Note It is important not to mix up the Haldex oil and the axle oil when changing the Haldex oil. Use of the wrong oil can cause irreparable damage to components.49DiagnosticsThe all-wheel drive control unit J492 can be selected with the vehicle diagnostic tester using address word 22. The following functions can be activated: • Control unit identification • Checking the SVM control unit configuration The validity of the software, the coding and the adaption channels for the vehicle is checked. • Event memory, Query and clear. • Actuator diagnostics To activate the actuator diagnostics, the internal combustion engine must be running, the temperature must be less than 60 °C and the vehicle must be at a standstill. If the actuator diagnostics are active, the multi-plate clutch is kept closed up to a speed of 6 kph. Driving the vehicle with the steering at full lock while the actuator diagnostics are active puts strain on the driveline, causing the rear axle to shudder. The multiplate clutch opens when the vehicle reaches a speed of 6 kph, noticeably relieving the strain on the driveline - an indication that the Haldex coupling is working. • Basic setting The basic setting function can be used to assign the Haldex coupling pump V181 to a matching characteristic curve stored in the all-wheel drive control unit J492. • Read measured data • Replace control unit Includes all the work operations necessary to replace the control unit. Replacing the Haldex coupling pump V181 The first thing to do after replacing the Haldex coupling pump is to correct the Haldex oil level. An actuator test must then be performed on the stationary vehicle and the oil level checked again. Finally, a basic setting procedure must be performed. Limp-home mode On the printed circuit broad of the all-wheel drive control unit J492 there are two temperature sensors which monitor the electronic components. The temperature of the multiplate clutches is calculated. Depending on the temperature threshold exceeded, the Haldex coupling is shut off. This is not indicated to the driver by a warning lamp.Freewheel mode of dual clutch gearbox 0D9 / 0CWIn models equipped with Audi drive select, the driver can select efficiency mode using the drive select button in the centre console or via the Car menu in the MMI depending on which infotainment systems are fitted (refer to page 58 ff.). In models with dual clutch transmission, an E is displayed in the instrument cluster for the selector lever position if efficiency mode has been activated and the selector lever is in D. Under these conditions, the dual clutch gearboxes attempt to open the clutches and interrupt power flow to the engine while the vehicle is coasting (in overrun). This action is based entirely on software in the gearbox and helps to save fuel, thereby increasing vehicle efficiency. If the clutches are open, the text "Freewheel" is displayed in the instrument cluster instead of the momentary fuel consumption. In addition to the aforementioned conditions, the following criteria are relevant to clutch opening: • Vehicle speed between 20 kph and maximum speed • Accelerator position 0 % – power flow to the engine is interrupted directly after the 0 % accelerator position is detected and the last gearshift has been completed. • Gradient  8 % – the gradient is measured by the longitudinal acceleration sensor of the brake electronics. Shut-off conditions: • The brake is depressed. • "tip minus" is selected on the steering wheel. • The selector lever is moved out of D. • The cruise control system is activated or is active. Activation or deactivation of the cruise control system does not constitute a shut-off condition. • Gradient  15 % • When the vehicle is travelling downhill, it accelerates to faster than the cruise control system's set speed. While the vehicle is freewheeling, the gearbox control unit preselects a gear suited to the speed at which the vehicle is travelling, thereby allowing the clutch to close comfortably at any time. The engine speed drops to idle speed during the freewheeling phase. If the freewheeling phase occurs at a high vehicle speed, e.g. 180 kph, the engine takes between one and two seconds to achieve the required synchronisation speed.609_172609_17450Selector mechanismY26 P R N D/SB1 B2 B3 B4 B5 B6 B7 B8 B9 B1031 +/- P F319 J587 E313RN D/S58dN110A1 A2 A3 A4 A5 A6 A7 A8 A9 A10Term. 31 P Term. 58d609_138Term. 30 Term. 15 Powertrain CAN bus, low609_139Selector lever position display unit Y26Powertrain CAN bus, highSelector lever position If the selector lever is in P, switch F319 is open. It is closed in all other positi