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Speed, lead from ABS (TC/ABS)

Speed, lead from ABS (TC/ABS)





the ABS or TC/ABS control module sends a speed signal to pin 64 on the Trionic T7 control module. The signal is a square wave that varies between 0V and B+, 29 times per wheel revolution. This speed signal is used to:


• determine, on manual gearboxes, which gear is used at the moment. This allows torque limitation in gears R and 1 and activation of the fuel shut-off in gears 2, 3, 4 and 5.

• activate speed limitation by limiting the maximum mass air flow/combustion at 240 km/h.

• prevent adaptation of idle speed control when the car is moving.




Diagnostics


• If there is no speed signal, diagnostic trouble code P0502 will be generated.

• The speed (bus from MIU) is used as a substitute value.


System reaction to a fault

Cruise control is blocked.