Hello Josvar.
I think the Ars system will be the ASR that has a car button.
It is Mercedes engineering technology, it is a control system in the traration system.
Cauasa for which it is activated, then an endless one as.
What state is the road. Dry, wet, frost ...
like the pressure of car's tires ...
the system itself serves to control the traction in the event that a wheel wheel will lose stability.
The system measures the RPM of the wheels through a sensor on each wheel.
Collect the information is passed to the switchboard and according to the information obtained governs the electrovalvulas of the ABS sending pressure to the wheel or wheels that lose stability.
Correcting its operation.
We expect a answer to the past to activate the ASR.
Anything you tell me and try to get information.
All the best.