Audi A4

Since 1994 of release

Repair and car operation

Speedometer in Audi A4, differently also could not be, is the electronic measuring device the same as also a measuring instrument of number of turns. It also processes impulses of number of turns which it (not how the tachometre) receives from the gauge 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 work of the indicator of an interval of maintenance service, the indicator of the expense of fuel, in volume control of a sound of a radio receiver and in work of the onboard 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 up a corresponding safety lock in a box of safety locks (the head the Electrotechnical equipment).

The 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 the data about run – the data about run continuously remains in the memory which independent of giving of pressure and is in the combined device.

The pulse gauge of a speedometer

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

That герконовый 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 gauge, influences a magnetic field influencing the block of contacts.

Check of the pulse gauge of a speedometer

Dismantle of the pulse gauge of a speedometer