Design

Design

Acceleration sensor, suspension





On the front suspension are two acceleration sensors, one on each spring strut. These measure the speed of vertical change. The sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensors is approximately 2.5 V. When there is vertical movement the signal will oscillate around this value; the greater the movement the greater the deviation. The control module calculates a damper position and speed from the acceleration. The control module uses the position and speed to determine the required damping force.

There are diagnostics for the acceleration sensors.

Position sensor, suspension





There are two position sensors at the rear suspension. The position sensor measure the position of the right and left-hand control arms in relation to the car body. The vertical position of the shock absorber is calculated based on this position. The sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensors is approximately 2 - 3 V. When there is vertical movement the signal will oscillate around these values; the greater the movement the greater the deviation.

NOTE: The values move in different directions on the left and right-hand sides. Upwards body movement results in increased voltage on the left-hand side and a voltage drop on the right-hand side.

There are diagnostics for the position sensors, which must be calibrated after replacement.

Acceleration sensor, car body





There are three acceleration sensors on the car body. Two are under the headlamps and one is behind the left-hand wheel arch in the cargo compartment. The acceleration sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensor is approximately 2.0 V. When there is vertical movement the signal will oscillate around 2.0 V; the greater the movement the greater the deviation. The control module assesses the information from the acceleration sensors and then controls the damping forces to the car body depending on the selected driving mode.

NOTE: The acceleration sensors are installed with the connector turned upwards and are fixed in position. Otherwise movement could result in incorrect values, resulting in poor cornering characteristics for example.

There are diagnostics for the acceleration sensors.

Shock absorber





NOTE: The illustration is of a front shock absorber.

Each wheel has an adjustable shock absorber. The damping force in the shock absorber is altered using a valve in the shock absorber which is affected by the current in the surrounding solenoid.

The suspension module (SUM) controls the current to the solenoid. Lower current gives lower damping forces, high current higher damping forces. If there is no current to the solenoid, the shock absorber is set to a failsafe mode, corresponding to conventional passive shock absorbers.

There are diagnostics for the solenoids.

Keypad for the driving mode (R line)





Above the ventilation shutter in the center console is a keypad which is used to select the driving mode (ACTIVE CHASSIS SETTINGS).

There are three different driving modes which can be selected:
^ COMFORT
^ SPORT
^ ADVANCED.

In the "COMFORT" driving mode, ride comfort is prioritized. In "SPORT" mode driving pleasure is prioritized.

The "ADVANCED" mode sets the shock absorbers to a characteristic optimized for more aggressive driving.

The selected driving mode is confirmed by an LED which lights in the keypad.

The keypad is connected via a cable directly to the suspension module (SUM).

The lighting has a rheostat function, i.e. the light level is set via the light switch in exactly the same was as for the combined instrument panel and the radio.

There are diagnostics for the keypad.

The switch for driving mode (not R line)





The Four-C switch is beside the other switched on the lower section of the climate control module (CCM).

There are two different driving modes which can be selected:
^ COMFORT
^ SPORT.

The "COMFORT" driving mode is active when the switched is not activated. The "SPORT" mode is activated when the switch is pressed. This is confirmed by a green LED in the switch.

In the "COMFORT" driving mode, ride comfort is prioritized. In "SPORT" mode driving pleasure is prioritized.

The switch on the climate control module (CCM) is connected to the central electronic module (CEM). The central electronic module (CEM) is in turn connected to the suspension module (SUM) via the Controller area network (CAN). There are diagnostics for the climate control module (CCM).