I need help trying to diagnose an issue I have bee having for months with my backup assist. I have read through the sticky on this site, however it did not cover the problem I am specifically having and could use your help. I would like to avoid going to the dealer to diagnose something I could fix myself.

2005 jag x-type
The issue is that when the vehicle is put in reverse the backup assist begins to beep rapidly as if something was three feet away from the bumper. It is not a steady beeping, and sometimes goes to a solid tone, almost as if it was detecting the ground. Rolling makes it change pitch and frequency of the beeping.
My suspicion is a sensor. After reading the sticky, I checked each one to see if they are clicking, which they are. All of them seem to function correctly because the constant beeping becomes solid if you approach the car from the rear, and then the beeping slows down if you back away.

I am looking for ways to self diagnose this issue.
If you unplug each sensor and drive with only three, do they continue to work correctly or does that screw up the mechanism? I was thinking that if it was a single bad sensor I could just unplug one at a time and see if I can find the faulty one that way. Or do they all need to be connected for the system to work?
If anyone can toss me a few ideas I would really appreciate it.

 

Are the surfaces of the sensors clean? Have you backed into anything? During the winter if I back into a parking space with a snowbank at the and and touch it I've gotten snow stuck in the sensors. They seemed to behave like you describe. Cleaning them of the stuck snow cured the problem.
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Jaguar - it's not an automobile, it's a Motorcar

 

You can't disconnect them one at a time. They run in series. If ones out you get a solid tone of 5 secs when you first start the car and put it in reverse, and then it becomes not operational. Make sure you don't have something interfering with the sensors. Make sure they are clean.