When i put the RR into reverse or D at the house the reverse sensor beeep noise comes on but stays on with a constant screech,even though nothing is in front or behind???.When i change intio D, to drive off forwards the screech stays on until i reach a certain speed then knocks off. I have checked the sensors and all ,both front and back are clicking???I had the engine,gearbox and transfer box ecu's all updated about a week ago,could this be at fault??? Any ideas......

Did the constant tone thing happen as soon as you got in it after updates or has it been a while afterwards?

Really need to get the fault codes read TBH

It could be one that even though its clicking to show its working the relay, it may have a dodgy circuit giving greater or less resistance meaning it thinks its got something in front of it. Bodsys Brake Bible
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It worked fine for a week or more after the upgrades, forgot to mention, i have no error codes????

Had this problem on my 58 plate RRS TDV8 last year during the really wet spell and JLR replaced both front and rear PDC sensor wiring harnesses under warranty because of "water ingress".

It stops above a certain speed because the PDC switches off above a certain speed until reverse gear is seected again

Good luck...

Just thinking about what you said and mine only gives trouble in damp wet weather ???more investigation???

Any one got the part no,s for the harnesses??

Did you get this sorted

I hope he did otherwise having that screeching for 7 years would drive you crazy