Pressure based systems look at air pressure to determine if the vehicle is level or not. While these systems are a step up from a manual control panel, they are essentially an air pressure pre-set and cannot really determine if the vehicle is actually level or not. For example, if you pre-set an air pressure of 80psi in the rear airsprings and then place an extra 200 pounds of people, luggage or fuel in the rear of the car, the air pressure will rise and the ride height will be lower. A pressure based system will actually deflate the system to restore its correct air pressure. This makes the leveling problem even worse! The ride height based system will sense that the vehicle is too low and add air until the correct ride height is achieved. This is what really needs to be done to restore alignment and ride quality characteristics. The height of the airspring is much more important than the air pressure. Air pressure is only one indicator of potential ride height.

Pressure based systems are, however, relatively inexpensive to purchase and easy to install because there are no ride height sensors to mount or run wiring to. In addition, pressure based systems are typically compatible with many different airvalves while ride height based systems may have a proprietary airvalve.