Just started getting a warning on my 22 F250. “Rear Park Aid N/Av. Sens. Bl.” Any ideas what it means, before I try to set up an appointment with dealer. Appointments are about 90 days out.

 

Any chance there is ice or dirt on the sensor?

 

The super duty truck is famous for getting moisture in several connections near the spare tire, where the left frame rail attaches the rear bumper and hitch. There are several connectors up in there. Clean them out, removing moisture and corrosion and coat with a light film of dielectric grease.

After that, check for sensor obstruction and make sure the sensors are all securely plugged in.

On Edit: Seems like I recall some one on FTE saying that one day, out of the blue, his rear park aid just didn't like his massive trailer hitch. But I think his failure mode was different.

 

I wiped them off the first time it happened with no help. So today I washed each sensor and it didn’t go off this last trip. But living in Alaska in winter they will always have snow, ice or dirt on them. The back up sensor works just fine. I just get the warning when I place truck in reverse and it goes out within a couple seconds.

 

Not sure of your truck's problem, but we have long winters with frequent snow here and I carry a gas station style squeegee scrubber combo tool and I wipe the snow buildup off the back lights and bumper usually each time I stop, and it keeps the reverse sensor from going off.