What is the purpose of the tractor protection valve?
a.To protect the trailer brakes from overheating
b.To keep air in the tractor brake system if the trailer breaks away or develops a bad leak
c.To regulate fuel flow to the engine
d.To lock the kingpin into the fifth wheel
Explanation
The tractor protection valve keeps air in the tractor brake system in case the trailer breaks away or develops a serious air leak. It prevents the tractor from losing all its air pressure.