Speed, Wire From ABS

The 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 0 V and B+ 29 times per wheel revolution. This speed signal is used to:
- prevent adaptation of idle speed control when the car is moving.
- on manual gearboxes, determine which gear is currently being used. This makes it possible to limit torque in gears R and 1 and activate fuel shut-off in gears 2, 3, 4 and 5. Control of the SHIFT UP lamp also depends on the current gear.
- activate speed limitation, which is achieved by limiting the maximum air mass/combustion at 250 km/h.

Diagnostics
- If the speed signal is missing, diagnostic trouble code P0502 will be generated.
- If the speed value is implausible, diagnostic trouble code P0501 will be generated.

System reaction to a fault
- Speed (bus from MIU) used as substitute value
- Cruise control blocked.