Automatic Level Control

Sensor 

The following applies to cars without Four-C (Continuously Controlled Chassis Concept) 

An inductive position sensor reads the angle between the body and the left rear control arm. The angle is a indication of how much the vehicle is leaning (chassis height) and depends on weight distribution.

• The sensor is mounted slightly differently for FWD and AWD.
• The rear electronic module (REM) reads off an analog signal (0.5 - 4.5 V) from the position sensor and converts it to an angle value (±35°), which is sent to the central electronic module (CEM).
• A fully loaded vehicle generates a signal of 0.5 V, which corresponds to negative 35°.
• The central electronic module (CEM) regulates the headlight levelling motors (PWM signal) to adjust the headlights vertically.

The following applies to vehicles with Four-C 

Two sensors read the angle between the body and the left and right rear control arm. The angle is a indication of how much the vehicle is leaning (chassis height) and depends on weight distribution.

The sensors are mounted slightly differently for FWD and AWD.

The suspension module (SUM) reads off the signals from the sensors and converts them to an angle value. The value is sent to the central electronic module (CEM) via the CAN network. The central electronic module (CEM) uses the information to regulate the headlight levelling motors.

Level control 

Regulation at speeds below 4 km/h (2.5 mph) 

When the ignition is switched on, the position sensor is read and the headlight levelling motors adjust the headlights.

Regulation at speeds above 4 km/h (2.5 mph) 

The headlights are regulated if there are great angle changes while driving. Regulation is time-dependant so that the system does not react to short changes, such as unevenness in the road surface.

Calibration 

The position sensor must be calibrated after work on the rear suspension. Perform calibration as described in the tab DIAGNOSTICS/VEHICLE COMMUNICATION, Rear electronic module (REM).