Thanks for your thoughts. I'll let you know how I get on.

Ok, update on my parking problem. The front and rear sensors work fine at idle, however if I increase the revs just a fraction the front sensors give a constant tone. Having the Icarsoft connected I can see that all sensors are still showing a safe distance so I should not get a constant tone.
So far I have changed the parking aid control unit and the front parking sensor loom and sensors for second hand ones. I used Sdd to enable the replacement control unit.
No fault codes are present.
I am running out of ideas now. I hope one of you smart people can help.

I know it's been mentioned earlier in the thread but the part might be the issue, why not remove the sensor you replaced and see if the tone is still constant with the others? Two people would help...and I've not had to re and re a sensor so IDK if one disconnected would cause the entire array to malfunction..

Done that. Thanks for your response though.

It will not work at all with one sensor removed. I did however replace the changed sensor with a genuine one. Still the same.

Obviously, the issue now seems to be electrical/voltage related, a bridge/ground somewhere in the array setup? Once it's triggered it goes straight to full tone. Since, I'm guessing, I'll wish you good luck. I am certain you will find it.

From what I can see everything is fed from the Parking Aid Control Module including power and earth.

See pages 65 and 66 below for wiring.

Earth Point is G4D151B-1 in last linked diagram. (Rear corner of car)

https://www.freel2.com/gallery/albums/user...TS_LHD.pdf

https://www.freel2.com/gallery/displayimag...amp;pos=40

PS If you are looking for damage to cable runs, it looks as if there is quite a long run from front sensors to module in boot, including a couple of connectors (resistive ??).
Have you noticed any other seemingly unconnected electrical problems ? - example - with front lights.

As you appear to be looking in all the right places, now is the time to step back and review for other clues. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

Great advice, from everyone. Thank you.
Checked all the wiring. Resistance checked all the runs
Finally I started again with the front sensors. At the beginning, I had one sensor with a fault code and it was constantly reading a max distance distance (2.55m) I replaced that sensor. But it did not solve the problem. Then, despite the other 3 sensors reading ok, I swapped them all one at a time. I just went through this process again and changing the right inner cured the fault. I can only assume that I somehow did not swap that sensor the first time but refitted the original.
I suspect that the rogue sensor, although it read correctly, was breaking down at above idle voltage and was sending noise to the control unit.
Lots of knowledge gained and lessons learned. Especially the correct 5 minute way to remove and fit the front bumper without removing headlights and wheel arch panels.

"Especially the correct 5 minute way to remove and fit the front bumper without removing headlights and wheel arch panels."

OK, enlighten us please. Andy
Freelander2 HSE (59 Plate, MY10 spec)

Ok, no problems. I'll start a new thread on it. In the next day or so.