AIRmatic, function - GF32.22-P-0003GZA: Notes

MODEL 164.8

with CODE (489) AIRmatic (air suspension with level adjustment without ADS adaptive damping system)

with CODE (494) USA version

Fig 1: Identifying Airmatic Control Unit (Model 164.8 With AIRmatic)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 2: AIRmatic Function Diagram (Model 164.8 With AIRmatic)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Basic function

When the air compressor delivers air to a bellows, the vehicle level increases at the wheel concerned. Conversely, the vehicle level decreases if air escapes into the atmosphere through the pressure release valve of the AIRmatic compressor unit (A9/1). The system is equipped with a central reservoir as a compressed-air reservoir. This increases the adjustment speed when raising the vehicle and permits regulation in the sleep and run-on mode.

The complete function of AIRmatic can be subdivide d into 2 subfunctions:

Level control enables a manual, as well as a speed-dependent automatic raising or lowering of the vehicle level.
The electronic level control system controls the vehicle level at the front and rear axles and ensures the vehicle level remains constant according to the driving and vehicle loading conditions.

Advantages of AIRmatic

Greater driving safety and ride comfort due to:

speed-dependent level control;
lowering of vehicle level with sporty driving style and at high speed so that no compromises in vehicle dynamics have to be made;
adaptation of suspension to road surface condition and driving style;
reaching a lower center of gravity position;
reaching a lower aerodynamic drag and thus a lower fuel consumption;
less lift at front axle;
an individual adaptation by increasing the vehicle level for poor roads or when offroad;
indication of the raised and lowered vehicle level stages by a function indicator lamp in the level adjustment switch (N72/1s2), and a warning given on the multifunction display (A1p13) in the instrument cluster (A1) if the vehicle level is too high.

Function overview

The functions of the pneumatic control loop of the AIRmatic are controlled with the components of the electrical system and electronic system.

The AIRmatic control unit receives input signals from the following components via the CAN data bus:

ME-SFI [ME] control unit (N3/10)
Fully integrated transmission control (VGS) control unit (Y3/8n4) (target and actual gear)
Central gateway control unit (N93)
Instrument cluster (outside temperature and circuit 61 "engine running")
Level adjustment switch
Steering angle sensor (N49)

The AIRmatic control unit receives input signals from the following components via discrete inputs:

Left front level sensor (B22/8)
Right front level sensor (B22/9)
Left rear level sensor (B22/7)
Right rear level sensor (B22/10)
AIRmatic pressure sensor (Y36b1)

The AIRmatic control unit controls the following control functions on the basis of the input signals:

Level control
Level adjustment

Several control functions can be processed at the same time.

In the AIRmatic control unit, the input signals are converted into output signals for the following components:

Actuators of level control and level adjustment

Air compressor motor (A9/1m1) via AIRmatic relay (K67)
AIRmatic pressure reduction valve (A9/1y1)
AIRmatic valve unit (Y36)

For driver information

Multifunction display in instrument cluster
Indicator lamp in level adjustment switch

	AIRmatic driver information		GF32.22-P-0003-01GZB
	AIRmatic - location of the electrical / electronic components		GF32.22-P-0003-03GZA
	Level adjustment, function		GF32.22-P-4005GZ
	AIRmatic level adjustment, function		GF32.22-P-4004GZX
	Pressure supply, function		GF32.22-P-4010GZ