I have a Tennant M30 sweeper. The problem I am having is when you try to raise the hopper the engine does not go into high speed. The engine stalls when hopper switch is pressed to go up. If I hit the engine high speed button by it self the engine does the same thing. It stalls and has no engine high speed. When i go to self test mode it shows P2-26. Has anybody had this issue before and can recommend anything?