Vehicle Speed Sensor: Description and Operation

The input of the driving speed signal (V-signal) is required in the DME control unit for several functions.

- On vehicles with the air conditioning switched on compressor activation is interrupted up to a driving speed of 13 km/hr when accelerating under full load.

- Idle control.

- Increasing deceleration fuel cutout. At a very low driving speed, the threshold for the deceleration fuel cutout is increased in order to avoid the engine stalling (e. g. driving over curbstone).

- Poor road detection. Poor road conditions also influence smooth running of the engine and can be interpreted as misfiring by the misfiring detection function. In order to avoid this situation, the misfiring detection function is blanked out for as long as poor road conditions are detected.