Speed information for other systems

Several other systems in the car must be aware of the vehicle speed. The TC/ABS unit places information on the wheel speed on the P-bus. This information is corrected in the main instrument unit using a factor that is dependent on the programmed tire size. The main instrument unit places the information on the vehicle speed on the I-bus.

For more information concerning bus communication, see SYSTEM OVERVIEW .

Certain systems (not Saab standard) may require a signal from the wheel sensors. TC/ABS therefore generates a square wave directly from both the sensors on the rear wheels. See also CONTROL MODULE CONNECTIONS