If it is raw diesel and it is that bad you should see something on the ground when you park and start up the next time and if it is diesel exhaust smell you should see soot in the area where it is leaking. If it is exhaust I don't know if it would set off any of the alarms inside the coach. Fuel leak is a fire bomb going down the road, exhaust a good way to go to sleep going down the road.
Last week when changing out my air filter I seen fuel dripping from the bell housing, removed the floor and it was the fitting coming out of the back of the head a plastic 1/2" return line to the tank. Removed the fitting and installed a compression style fitting replacing the push on air style fitting.
JR