I believe that indication is a generic warning light indicating an out of range reading on one or more of your engine or transmission sensors. Given the year of your coach, if it is powered by a Cummins, the oil pressure sensor may very well be the problem. Check your guages during start up and if the light goes on while driving.
If all the engine functions are operating correctly it could be a faulty sensor. The oil pressure sensor was a known issue.
Peter - Doctor of Mixology