Audi A4

since 1994 of release

Repair and car operation

A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ exhaust System
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and absorption channels
+ injection System
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ ignition System
+ Lighting
+ Alarm equipment
- Tools and devices
   Check of control tools and bulbs
   The combined device
   Indicator of amount of fuel
   The indicator of temperature of cooling liquid
   Auxiliary devices
   Control bulbs above in the combined device
   Control bulb of cooling liquid
   Control bulb of level of brake liquid
   Control bulb of pressure of oil
   Control bulb of indexes of turns
   Control bulbs in devices of a round form (and nearby)
   Control bulb of indexes of turn on the trailer
   Control bulb of ASR
   Control bulb of the lock of ignition
   Control bulb of headlights of a driving beam
   Control bulb of a safety cushion
   Control bulb of ABS
   Control bulb of the parking brake
   Control bulb of a battery charging
   System of autocontrol of the car
   Ignition lock
   Check of switches
   Alarm buzzer of lighting
   Warmed back glass
   Check of screen wipers and stekloomyvatel
   Engine of screen wipers
   The help at malfunctions
   The liquid gulf for washing of glasses
   System of washing of headlights
   Mirror adjustment with the electric drive
   Central lock
   Window regulators with the electric drive
   Sliding/demountable roof with the electric drive
   Radio receiver
   The aerial on back glass
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics


Speedometer in Audi A4, differently also could not be, is the electronic measuring device as well as a measuring instrument of number of turns. It also processes impulses of number of turns which it (not how the tachometer) receives from the sensor on a transmission. There it is measured, with what frequency wheels rotate.

The signal of rotation of wheels is used as measuring size for run definition, and also in operation of the indicator of an interval of maintenance, the fuel consumption indicator, in volume control of a sound of a radio receiver and in operation of the board computer. Therefore there was an idea to send this signal and on a speedometer and to refuse a shaft of a speedometer which provides a drive in old mechanical speedometers.

If the speedometer does not work, in the beginning check the corresponding safety lock in a box of safety locks (head the Electrotechnical equipment).

Run counter

Indication of the general and day run in Audi A4 is carried out by the liquid crystal display. That it was impossible to manipulate data on run – data on run continuously remain in the memory independent of giving of tension and being in the combined device.

Pulse sensor of a speedometer

Impulses of rotation of wheels move in a speedometer the sensor with gerkonovy contact behind on a transmission. Gerkonovy contact represents the block of contacts which are placed in an air-tight gas cover. Contact becomes isolated in case it is influenced by an electromagnetic field.

In order that gerkonovy contact could give out sequence of impulses, it should open and be closed in beat frequencies of rotation of wheels. Therefore the wheel with dredging which rotates in front of the sensor, influences the magnetic field influencing the block of contacts.

Check of the pulse sensor of a speedometer


  1. Lift the left forward wheel.
  2. Press a fixing clip on the socket and remove the socket.
  3. Connect to both contacts of the sensor an ohmmeter.
  4. Now slowly turn a hand the left forward wheel: the indicator of an ohmmeter should fluctuate between 0 Ohm and Ohm.
  5. If it not so, replace the sensor.

Dismantle of the pulse sensor of a speedometer


  1. Press a fixing clip on the socket and remove the socket.
  2. Slightly press down a clamp of a fixing clip of the sensor and slightly turn the sensor to the right.
  3. Take out the sensor from a transmission.
  4. At installation track correctness of installation of sealing rings.