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Speed, lead from ABS

Speed, lead from ABS



The ABS control module sends a speed signal to control module PSG 16 on pin K34. The signal is a square wave that varies between 0 V and B+ 29 times per wheel rotation. This speed signal is used to:


determine the gear currently engaged. This ensures the engine receives the correct amount of fuel in different gear positions when the accelerator pedal is released.

provide an impulse for cruise control.

activate speed limitation by throttling down fuel quantity/combustion at 225 km/h




Diagnosis


If the speed signal exceeds 220 km/h, is constantly high/low or is incorrect, DTC P0500 will be generated.



System reaction to a fault

Cruise control is deactivated.

ACC is deactivated.

The speedometer does not work.