How It Works

WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2006 BMW 530i, 2006 BMW 525i, 2006 BMW 330xi, 2006 BMW 330i, and 2006 BMW 330Ci. However, it is still accessible from the selected car via links, so may be relevant.

The AL control unit is integrated into the on-board network by the powertrain CAN and the chassis CAN. The function algorithms for calculating the nominal values for controlling the electric servomotor are stored in the AL control unit. In addition to the actual system functions, the control unit has the following functions:

Control Of The Power-Steering Pump
Pre-Drive-Check:
The AL control unit is initialised after the ignition is switched on (pre-drive-check). The electric servomotor is not actuated while initialisation is in progress. The sensor signals are checked and, if necessary, calibrated.
Safety Monitoring Functions:
If errors are detected either the status changes directly to "Error" or rate-of-yaw control is deactivated. When system status is "Error", activation of the electric servomotor is disabled. System status changes to "Drive" once initialisation has completed successfully.
Sensor Plausibility Check
Actuator Monitoring
Vehicle Authentication:
Check with the Car Access System (CAS control unit) to ensure that drive authorisation has been verified.

The AL control unit uses the various input signals to compute the signals for actuating the electric servomotor. Input signals are:

Wheel speeds (wheel-speed sensors via DSC)
Yaw rate and lateral acceleration (from the DSC sensor or sensors)
Steering wheel angle (from the steering angle sensor)
Cumulative steering angle (from the cumulative steering angle sensor)
Position of the electric servomotor (from the motor-position sensor)