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Wheel-speed signal output

Wheel-speed signal output


Several other systems in the vehicle need to know the wheel speed. The ESP control module is connected to the P-bus and transmits information about the speed of each wheel.

This information is processed in the main instrument unit into vehicle speed in km/h (mph). The speed is corrected to the tyre size that has been programmed. This vehicle speed is then sent out over the I-bus.

The engine management system is connected to the P-bus and therefore has access to the same speed information.

Note

In cars with a 2.2 l diesel engine, vehicle speed data is sent directly from the ESP control module (pin 40) to PSG 16 (pin 34).




Speed information can be sent even when the ABS, foot brake, ESP OFF or central warning lamps are on. The information is sent as long as one of the rear wheel sensors is working and the control module is working and supplied with power.

For more information on wheel speed on the bus, see Electrical systems, Bus and diagnostic communication, System overview and Main instrument unit, System overview .