Audi 80/Avant (B4)

since 1991-1995 of release

Repair and car operation

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ injection System
+ Coupling
- Transmission and transmission
   Removal and installation of a mechanical transmission (KP)
   Noise in a transmission
   Automatic transmission (AKP)
   Electronic control of AKP
   Main transfer
   Power shafts
   Check of cuffs of power shafts
   List of malfunctions
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrosystem
+ ignition System
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Electronic control of AKP

The scheme does by more evident communications between the block of valves of switching (1) AKP, the selector (2) lever the multipurpose switch (3) and the electronic control unit (4). The manual valve (5) is actuated directly by the switching lever.

Entrance signals

The control unit processes numerous signals from various knots; information arrives from:

  • The AKP selector lever with the multipurpose switch. Management of inclusion of headlights of a backing, starter blocking depends on position of the lever at the included mode of movement and management of system of change of a mode of movement.
  • The Sport button which is switching on the sports program of switching.
  • Butterfly valve potentiometer about the provision of a butterfly valve. This acquaintance on injection system an element serves for definition of the moments of switching.
  • The sensor of speed in AKP for determination of speed of movement also for the switching moments. In case of malfunction of this sensor the control unit uses frequency of rotation of a shaft of the engine (from the Hall sensor) as a spare indicator.
  • The sensor of limiting provision of a pedal of an accelerator in a hummock drive of "gas"; he reports, if the pedal of an accelerator was squeezed completely out. In this case switching on an overgear occurs after, in need of AKP switches to two ranges down.
  • The switch of a signal of braking for removal of blocking of the lever of switching. The switching lever from the situation "P" or "N" in one of ranges of movement can be moved only at the squeezed-out pedal of a brake.
  • The sensor of temperature of ATF reporting about temperature of liquid in AKP. Considerable heating of ATF can come a consequence of strong distinction of number of turns between the engine and AKP. If in the control unit the signal «the increased temperature» arrives,

AKP in separate ranges switches to an overgear later. It reduces a proskalzyvaniye in the hydrotransformer and reduces ATF temperature – then again there is a switching on the usual program of movement.

Management of switching processes

If you move the selector lever in situation "D", being under the pressure of ATF gets to so-called valves of switching in the block of valves which, in turn, hydraulically operate multidisk couplings and multidisk brakes. The Digimat control unit regulates pressure by means of electromagnetic valves and thus defines time moment for switching on raised or a low gear, and also switching transitions. It is at the same time kept in contact with the control unit of systems of injection/ignition – when switching on an overgear the ignition moment moves back in order that transition of switching passed smoothly a little.

Teams from the control unit get further on a magnet of blocking of the lever of switching, the relay of blocking of a starter and headlights of a backing and the light indicator in the Sport button. If the Audi 80 car is equipped with system of regulation of speed, a food on it starts to move with the control unit only when one of ranges of advance and speed is included for the first time reached border of 30 km/h.

Independent diagnostics

The AKP control unit can distinguish and write down arising malfunctions. The control program watches entrance and target signals practically all sensors and knots, and also behind their electric chains. Arising malfunctions register in long-term memory of the store. At the corresponding check in a workshop memory of the store is read out by means of the special device. Possibilities of check of memory of the store in house conditions do not exist. Even if you assume malfunction existence in AKP management, interrogate memory of the store of malfunctions you can only in Audi workshop.

Operation in extreme conditions

If the control unit fixed the malfunction which is essentially influencing functioning or if the control unit is faulty, it is switched in a mode «operation in extreme conditions». For this purpose there are two programs:

  • As well as before failure detection, AKP is switched automatically on raised or a low gear, but breakthroughs when switching become considerably more expressed.
  • AKP is not switched any more automatically on raised or a low gear. In positions of the lever of the selector "D", "3" and "2" on hand there is only the third range. Only in provisions "1" and "R" the chosen range really joins.
    In both cases it is necessary to visit urgently Audi workshop where memory of the store of malfunctions first of all will be interrogated.

AKP check

AKP almost does not provide possibilities for manifestation of own initiative in house conditions. Purposeful checks, however, help to estimate a cause of defect that is not least interesting upon purchase of the second-hand car:


  1. At malfunctions first of all it is necessary to check ATF level in AKP.
  2. If ATF on a tip щупа smells burned down, means, there is a serious damage of AKP. In this case multidisk couplings or brake tapes are defective.
  3. During a trial trip it is possible to check the switching moments.
  4. From this, how there are switching processes, it is possible to draw a conclusion on AKP condition.
  5. Regulation of a hummock drive of gas with the integrated sensor of limiting provision of a pedal of an accelerator – an important condition for excellent job.
  6. The same it is possible to tell about regulation of a hummock drive of the lever of the selector.

Supervision over switching processes

During a trial trip you should pay the attention to switching processes:

  • Switching on an overgear: at short squeezed-out pedal of an accelerator switching is almost imperceptible; at completely squeezed out pedal of an accelerator (at a troganiye from a place or during movement) gear shiftings become more appreciable, but the overgear should join smoothly. Short-term increase of turns at change of transfers indicates malfunctions in which it is necessary to be engaged more densely.
  • Switching on a low gear: at the released pedal of an accelerator (at movement nakaty) and very low speeds almost imperceptibly. Breakthrough when switching on a low gear on incomplete or full "gas" is quite normal. Switching on a low gear the selector lever at the released pedal of an accelerator lasts 1 — 2 pages. If when switching by the lever of the selector the accelerator pedal is at the same time squeezed out, change of transfers should occur immediately.

 Help: Audi 80 with an automatic transmission cannot be towed further, than on 50 km, differently there is no AKP greasing. For the same reason when towing it is impossible to exceed the maximum speed in 50 km/h. In somnenitelny cases it is better to choose shorter way or to cause the wrecker.

AKP removal

The car is necessary for raising and reliably to fix. You also will need a big garage jack for a podderzhivaniye and lowering down very heavy AKP.


  1. To disconnect the accumulator.
  2. To disconnect a wire tip to the tachometer sensor.
  3. At models with the 6-cylinder engine to remove the inlet channel. For this purpose to disconnect vacuum hoses, to remove an airwater hose and to turn out fixing bolts.
  4. At models with the divided bulk branch pipe of ATF to weaken it above and to extend. The lower part of a branch pipe to stop up with not fibrous rag.
  5. To turn out the bolts connecting the engine and AKP which it is possible to reach from above.
  6. To raise hoses of system of cooling.
  7. To bring under the engine reliable support, to prevent capsizing.
  8. To turn off the bottom panel of a motor compartment.
  9. To remove thermal protection of a leading semi-axis.
  10. To remove body traverses below an exhaust pipe or catalytic converters (depending on engine type).
  11. To remove exhaust pipes (at models with the 6-cylinder engine together with catalytic converters).
  12. To disconnect power shafts from a transmission (let's fall it).
  13. To remove a starter. Thanks to it access to fixing bolts of the hydrotransformer opens.
  14. To substitute capacity under boltovy connections of ATF lines.
  15. To separate the pipeline to ATF cooler at level of the oil pallet.
  16. To turn off fastenings for the ATF pipeline and to take hoses aside.
  17. To weaken in total three bolts of the hydrotransformer from the engine.
  18. For this purpose to hold the central bolt of a pulley or a damper (depending on engine type) by means of a cap wrench. To turn a cranked shaft respectively on 1/3 turns.
  19. To turn off a heat-shielding of the multipurpose switch.
  20. To remove the tip on the AKP case. After that to remove from loops trosoderzhatel of procon-ten system and to wring out cables upward.
  21. To turn off a forward arm of the engine.
  22. To raise AKP by means of a garage jack and to weaken bolts of fastening of AKP.
  23. The engine connected to AKP, slightly to overturn back; after that again to bring under the engine a strong support.
  24. To turn off a six-sided bolt of a rezino-metal support of an arm of AKP behind.
  25. To turn out the bottom connecting bolts fixing by AKP to the engine.
  26. To wring out AKP from the engine; if necessary to use mount.
  27. Carefully to lower AKP.
  28. At removal of AKP to wring out the hydrotransformer.
  29. The hydrotransformer should remain together with AKP! Watch closely that it did not drop out (to fasten a wire).

Installation of an automatic transmission

Installation occurs logically in return sequence in comparison to removal. The special attention is deserved by the next moments:


  1. To check, whether correctly in AKP the hydrotransformer is established. To watch that at installation it did not move forward.
  2. For hydrotransformer fastening to a flywheel it is necessary to use original bolts, differently the hydrotransformer it will be destroyed.
  3. At installation in the last turn to twirl bolts of a rezino-metal support. Before it a support to correct so that the core of a support was in the case middle.
  4. To establish a podkladny washer in thickness of 13 mm between a countersupport of a tube of system of cooling of ATF and AKP.
  5. If necessary to fill in new ATF.
  6. To establish an exhaust pipe.
  7. To adjust the selector lever.

Moments of an inhaling of fastenings of AKP

N • m
Primary shaft to Akpgidrotransformator to маховикуАКП to the engine
Arm to AKP
AKP arm to a body