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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.