Speed, bus from TC/ABS: Notes

WARNING: This page is about a different car, the 2003 Saab 9-3 and 2002 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Speed, Bus From TC/ABS - Control Module Communication Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Speed, Bus From TC/ABS - Control Module Communication Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The TC/ABS control module sends the bus message "Wheel speed, front right, XXX km/h" via the P-bus to the Trionic control module connections 19 and 66. 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 by limiting the maximum air mass/combustion at 240 km/h on B205E/L/R and 250 km/h on B235R.