4. Systemdescription · The wheel speeds, steering angle, vehicle speed, transverse accelerationand the brake pressure in the

4. Systemdescription The wheel speeds, steering angle, vehicle speed, transverse accelerationand the brake pressure in the brake master cylinder are measured and processed in the PSM control module. The control module is connected with the control modules of the engine -and for Tiptronic with the transmission management- by means of a CAN data bus. These digital line connections allow rapid data exchange betweenthe PSM, DME and Tiptronic control modules. The control module is constantlysuppliedwith current data about the enginetorque, accelerator pedal position and transmissionratio (for Tiptronic). The rate-of-turnand transverse acceleration sensors detect the forces which act to turn the vehicle around its centre of gravity. The longitudinaland transverse forces on the wheels can be calculatedfrom the value measurementslisted. If these values exceed certain control thresholds,the control module triggers the appropriate solenoid valves and the return pump in the hydraulic unit in order specificallyto apply defined brake pressure to one wheel or to several wheels. 45 -D 198 4503 Diagnosis/troubleshooting PSM System PSM05XX