Abstract: A system for detecting the air pressure in each wheel and for effecting inflation or deflation in each wheel while the vehicle is operating including a controller (30) and a high pressure reservoir (34) mounted on each wheel. Each controller includes a magnet (45) that is positioned responsive to the pressure in the associated tire and a stationarily mounted solenoid detector (32) senses the position of the magnet and generates a signal which is fed to a data processor (97) for the generation of an output signal to the vehicle operator indicating the pressure in the tire. Additionally, through actuation of the control, a current is passed through a coil (62) on the solenoid detector to actuate the magnet (45) in an individual wheel for opening a valve and allowing air to flow through the tube (39) into the tire for raising the tire pressure, or to allow the exhaust of air to lower the tire pressure.