The Proviso™ Plus P200A system is designed for controlling the self-steering lift axle on SPIF 21 and 23 trucks, with Air Ride suspension. This includes lifting the axle in reverse, with the 4-way flashers, and when the truck is empty. The system also lowers the axle when the truck is loaded.
The P200A also provides controls for locking the self-steering axle, a max load indicator, and an external valve heater.