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Audi 243 Service

Summary of 243

  • Page 1

    Service. For internal use only all rights reserved, including the right to make technical changes. Audi ag dept. I/vk-5 d-85045 ingolstadt fax 0841/89-36367 040.2810.62.20 technical status 11/00 printed in germany pneumatic suspension system part 2 4-level air suspension in the audi allroad quattro ...

  • Page 2

    2 the 4-level air suspension system in the allroad quattro is a logical development of the self- levelling system in the audi a6. The principles of the suspension/air suspension system and the description of those system components which are identical in the 4-level air suspension system are describ...

  • Page 3: Contents

    3 contents system description . . . . . . . . . . . . . . . . . . . . 4 the self-study programme is not intended as a workshop manual. The self-study programme will provide you with information on the design and functions of the different assemblies/systems. New note important: note page for mainten...

  • Page 4: Description of The System

    4 description of the system the vehicle level is determined separately at each axle side by means of 4 level sensors. Each air suspension strut is allocated a so- called air spring valve (transverse check valve) so that each axle can be controlled individually. Front right air suspension strut rear ...

  • Page 5

    5 the 4-level air suspension system is designed as what is known as a pressure accumulator system. The pressure accumulator system increases system availability, reduces noise development and protects the power supply. One of the special features of the system is the ability to alter the ground clea...

  • Page 6: Description of The System

    6 description of the system • the 4 level stages can be controlled manually or automatically within defined limits (see page 8 onwards). • individual automatic functions or the entire system can be switched off via the control system. • leds in the operating unit indicate the operating status and th...

  • Page 7: Operation and Display

    7 operation and display operation the self-levelling control unit e281 is used to control the 4-level air suspension and the display/monitor the system status. Certain level changes occur automatically during normal driving (see control strategy). Within defined conditions (see control strategy) the...

  • Page 8: Operation and Display

    8 operation and display if the actual level deviates greatly from the reference level, this is indicated to the driver with flashing leds (according to a level change). Significant deviations are: – at least one axle level is below the next level down. – both axle levels are above the next level up....

  • Page 9

    9 243_022 243_023 243_024 243_025 other button functions automatic switching the so-called “manual mode” can be switched on or off by pressing the “raise” or “lower” button for at least 3 sec. The yellow led marked “man” indicates to the driver that the vehicle is in manual mode. The automatic “park...

  • Page 10: Control Strategies

    10 if the vehicle is at high level 2, it will lower automatically to high level 1 at a speed of > 35 km/h. The system will respond to a request to shift to high level 2 only up to a speed of at a speed of > 80 km/h in high level 1, the system will automatically lower the vehicle to normal level.. Th...

  • Page 11

    11 motorway mode if the vehicle travels for longer than 30 seconds at over 120 km/h (vehicle is already at normal level), it will automatically be lowered to low level. This reduces air resistance (saves fuel) and lowers the vehicle’s centre of gravity (improved driving dynamics). Pl (=hl1) is only ...

  • Page 12: Control Strategies

    12 control strategies the vehicle rises automatically to high level 1 at the following speeds and time thresholds: if the system has lowered the vehicle to low level (motorway mode), it will automatically raise it to high level 1 when its speed drops below 60 km/h for longer than 30 seconds. Vehicle...

  • Page 13

    13 if, for example, the vehicle is at high level 2 with active esp influences and the driver accelerates sharply on a very winding route, speeds of > 35 km can be achieved in high level 2. In order to guarantee maximum safety in such driving conditions, esp influences are automatically deactivated a...

  • Page 14: System Components

    14 the air springs the front air spring is a new design. As on the rear axle, the air springs are combined coaxially with the dampers as a suspension strut. The rear air springs are identical in design and function to those of the audi a6 with self-levelling. Design while in the case of the rear sus...

  • Page 15

    15 rear suspension strut the bayonet connection must be absolutely clean and is greased with a special lubricant before installation (see workshop manual). For installation, the air spring is pushed on and then turned. Operating pressure of the air springs front rear minimum operating pressure 6.0 b...

  • Page 16: System Components

    16 system components 243_006 243_007 wrong correct air springs must not be moved when pressureless because the air bellows cannot unroll on the piston and would be damaged. In a vehicle with depressurised air springs, the relevant air springs must be filled with the aid of the diagnostic tester (see...

  • Page 17

    17 air supply the compressor the construction and function of the compressor corresponds largely to the unit described in the self-levelling suspension of the a6. The following is a description only of the differences in the 4-level air suspension system in the audi allroad quattro • the fitting loc...

  • Page 18: System Components

    18 system components a special mounting consisting of spiral springs and rubber damping elements prevents the transfer of vibrations to the bodywork. You can find a description of the design and function of the compressor as well as the filling and discharging procedure in ssp 242. 243_008 in normal...

  • Page 19

    19 pressure accumulator the pressure accumulator allows the vehicle level to be raised more rapidly with minimal noise as the pressure accumulator is only filled while the vehicle is in driving operation and the compressor noise is less noticeable (see air supply strategy). Provided that there is su...

  • Page 20: System Components

    20 system components p pneumatic diagram 1 additional noise damper 2 non-return valve 1 3 air dryer 4 non-return valve 3 5 non-return valve 2 6 discharge throttle 7 pneumatic discharge valve 8 compressor v66 9 electric discharge valve n111 10 pressure sensor g291 243_030 1 2 3 4 6 5 7 9 10 11 12 13 ...

  • Page 21

    21 the 4 air spring valves n148, n149, n150, n151 and accumulator valve n311 are combined in one valve unit. They are designed as 2/2 way valves and are closed without current. The pressure on the air spring side/accumulator side acts in the closing direction. The pressure lines are colour coded to ...

  • Page 22: System Components

    22 p temperature sensor g290 (overheat protection) to enhance system availability, temperature sensor g290 is attached to the cylinder head of the compressor. A temperature model is implemented in control unit j197 which prevents overheating of the compressor while simultaneously utilising the maxim...

  • Page 23

    23 vehicle level senders g76, g77, g78, g289 (level sensors) the level sensors are so-called angle sensors. With the aid of the connecting link kinematics unit, the height changes of the vehicle body are converted into angle changes. The angle sensor used in the audi allroad quattro is a contact-fre...

  • Page 24: System Components

    24 system components 243_033 243_037 for technical reasons, the voltage for the left- hand level sensors (front left g78 and rear left g76) is supplied by the headlamp range control unit j431. Power is supplied to the right-hand level sensors (front right g289 and rear right g77) by the 4-level air ...

  • Page 25

    25 the rotor consists of a closed conductor loop connected to the sender arm (rotates with the sender arm). The conductor loop has the same geometric shape as the receiver coils. Construction/design the angle sensor consists essentially of the stator and the rotor. The stator consists of a multilaye...

  • Page 26: System Components

    26 system components function the exciter coil is subjected to an alternating current which produces an electromagnetic alternating field, the induction of which is penetrated by the rotor. The current induced in the rotor produces a second electromagnetic alternating field around the conductor loop...

  • Page 27

    27 warning lamp k134... ... Illuminates for one second when terminal 15 is on (self-test). ... Is constantly illuminated in the case of relevant system errors or when the system is switched off. ... Is constantly illuminated during basic system setting and when basic system setting has not been perf...

  • Page 28: System Components

    28 f f f f f s f s s f 3 1 7 5 2/25 2/50 2/49 2/05 2/04 2/01 2/02 9 10 4 8 system components control unit j197 transmits the information concerning the vehicle level and the system status back to the e281 via the k wire, whereupon the electronic unit actuates the relevant leds. For self-diagnosis re...

  • Page 29: Interfaces

    29 can information exchange in the case 4-level air suspension, the information exchange between control unit j197 for the self-levelling system and the networked control units is performed via the can drive with the exception of a few interfaces. Interfaces the system overview shows the information...

  • Page 30: Interfaces

    30 the driving speed signal … ... Is a square-wave signal produced by the dash panel, the frequency of which is changed in accordance with the vehicle speed. ... Is required in the evaluation of the driving condition (stationary/driving mode) and thereby for selection of the control criteria (see “c...

  • Page 31

    31 1 2 3 1 2 3 7 8 4 9 6 5 13 bl nsl 31 58l rf br 30 34 58r 31 10 11 12 the trailer operation signal … ..... Comes from the f216 contact switch in the trailer socket. When the plug is connected, contact switch f216 connects control unit j197 to earth. See also “trailer operation”. Headlamp range con...

  • Page 32: Interfaces

    32 interfaces p t° m 1 a b c d 2 3 4 iv iii ii i 5 6 7 9 12 8 m m 31 functional diagram terminal 15 terminal 30 t.34 terminal 30 s s s n150 n151 n311 n148 n149 g291 v66 g290 n111 j197 g76 g77 g78 g289 j431 v48 v49 e281 243_038 j403 f216.

  • Page 33

    33 key to function diagram e281 self-levelling suspension operating unit f216 contact switch for switchable rear fog light g76 self levelling suspension sender, rl g77 self levelling suspension sender, rr g78 self levelling sender, fl g289 self levelling suspension sender, fr g290 compressor tempera...

  • Page 34: Control Concepts

    34 however, all level sensors (left and right) are required in the air suspension system run-up and run-on mode (ignition off). To allow the left-hand level sensors to deliver measured values in the case of the 4-level air suspension in the allroad quattro, power is supplied to control unit j431 (hr...

  • Page 35

    35 level change process: raising - rear axle first, then front axle lowering - front axle first, then rear axle modes height mode/driving mode reaction times upon level deviation control characteristics during level change level change is basically performed axle by axle, whereby level differences b...

  • Page 36: Control Concepts

    36 control concepts the system can switch between sleep mode and run-on/run-up mode, triggered via the door contact signal, a maximum of 15 times. For the 15 subsequent wake-up procedures, the system switches to sleep mode after only 1 minute. The system can then only be activated via terminal 15 an...

  • Page 37

    37 in trailer operation, normal mode must always be selected and care must be taken that the system is switched to manual mode (e.G. No automatic switching to manual mode if trailer operation signal fails). In difficult driving conditions, high level 1 or high level 2 can be selected, however, norma...

  • Page 38: Service

    38 special tools adapter cable 1598/35 with test box 1598/14 are used for fault finding and function testing of sensors and signals of the 4-level air suspension system. As the pin assignment of the test box is not compatible with the pin assignment of control unit j197, pin template v.A.G 1598/35-1...

  • Page 39

    39 basic system setting the basic system setting of the reference level in the 4-level air suspension system is performed by inputting body-level measured values at normal level. The measured value, the vertical dimension from the wheel centre to the wheel cut-out, must be input into the control uni...

  • Page 40: Service

    40 self-diagnosis address word: 34 self levelling suspension both generations of diagnostic tester (v.A.G. 1551/1552 and vas 5051) are suitable for communication with the 4-level air suspension control unit. Due to the limited capacity of the tester program cards, there are display text limitations ...

  • Page 41

    41 allroad quattro control strategies 4-level air suspension + additional shift stage 02 0 3 5 80 60 5 100 120 130 200 30 general overview control unit 4z7 907 553a/b esp saf e ty-switching a u tomatic lowering p a rking level control v >70 km/h: engine intervention v >50 km/h: acoustic and visual w...

  • Page 42: Notes

    42 notes.

  • Page 43

    43.

  • Page 44

    Service. For internal use only all rights reserved, including the right to make technical changes. Audi ag dept. I/vk-5 d-85045 ingolstadt fax 0841/89-36367 040.2810.62.20 technical status 11/00 printed in germany pneumatic suspension system part 2 4-level air suspension in the audi allroad quattro ...