Speed sensitive power steering
The central electronic module (CEM) (4/56) receives data from the engine control module (ECM) (4/46) via the control area network (CAN) that the engine is running and information from the ABS system (4/16) about the speed of the car. From model year 2001 the ABS module is called the brake control module (BCM). The central electronic module (CEM) then operates the stepper motor (6/71) via the four outputs to set the stepper motor to the correct servo assistance level.
The central electronic module (CEM) checks the signals. If a fault is detected, the servo assistance is set to normal (≈70km/h) and the system is disengaged. The central electronic module (CEM) also transmits a signal to the driver information module (DIM) (5/1) via the control area network (CAN) which lights the general warning lamp and displays a text message.