Looks like I’ve got a duff rear sensor, I’m getting the long beeeep at selecting reverse and the system isn’t working. Listening to the sensors I believe the faulty one is the outer near side one. I’ve tried sliding my hand up the bumper to release it but just can’t do much between the bumper and the crash bar. Typically, it’s probably the hardest one to reach...

I've got a Haynes coming so hopefully that will help me remove the bumper, but before I do, does anyone know a quick and easy way to release the sensor? Or is bumper removal my only option?

Thanks

Bumper off I'm afraid.

Remove rear wheels.
2 screws (1 on each arch) low down that hold the arch liners to the bumper bracket.
2 nuts (1 in each arch) in the back of the wheel arches under the liners, (remove carefully as the bolt heads are moulded into the plastic bumper brackets and can spin & rip the plastic easily. Use plenty of WD40 or plusgas and leave to soak.).
2 bolts on the boot lip.
2 bolts under the bumper that hold the plastic tabs sited there.

Sent from my SM-G965F (S9+)

That’s a pain in the ‘arris. Thanks for the info. 

Are they OEM or aftermarket?

My X-Vision ones appear to be a centre piecewith a round external ring. Appears that the centre fits separately to the outer ring (although I admit i've not been able to get any of my sensors out to re-paint them).

That's a coincidence, my rear sensors have started to do the same intermittently.. if I leave the car in reverse when I turn it off, even if nowt is behind me, when I start it up again the beeping starts constantly.. and sometimes when reversing it won't go off at all. 

Interestingly though the Haynes manual states u don't remove the rear wheels for bumper removal.. 

16 hours ago, Micro said:

Are they OEM or aftermarket?

My X-Vision ones appear to be a centre piecewith a round external ring. Appears that the centre fits separately to the outer ring (although I admit i've not been able to get any of my sensors out to re-paint them).

Mine are original. I’ve got the replacement and as you say it’s a lot smaller than the completed assembly. Luckily my cars black so painting won’t be a concern. 

1 hour ago, Dave1981 said:

That's a coincidence, my rear sensors have started to do the same intermittently.. if I leave the car in reverse when I turn it off, even if nowt is behind me, when I start it up again the beeping starts constantly.. and sometimes when reversing it won't go off at all. 

Interestingly though the Haynes manual states u don't remove the rear wheels for bumper removal.. 

Same symptoms as mine. I had to listen for the clicking noise from each sensor, which wasn’t the easiest task when you have hearing loss...

my haynes came today. I suspect without removing the wheels there may be more scraped arms / swearing but I’m used to that 😀

Finally got around to sorting this. It’s quite easy to do with the car on the road with wheels still on. Just needed a hex adaptor for my ratchet 1/4” ratchet so I could undo the arch liner screws. For info, with one side-worth of fasteners undone the outermost sensor can be accessed from above. 

Only issue I had was the scrivet underneath wouldn’t undo so had to cut it off using my pen knife...

Definitely worth soaking the bumper bolt in something as Stoney871 advised. 

Finally got around to sorting this. It’s quite easy to do with the car on the road with wheels still on. Just needed a hex adaptor for my ratchet 1/4” ratchet so I could undo the arch liner screws. For info, with one side-worth of fasteners undone the outermost sensor can be accessed from above. 
Only issue I had was the scrivet underneath wouldn’t undo so had to cut it off using my pen knife...
Definitely worth soaking the bumper bolt in something as Stoney871 advised. 

Glad to help.
Happy you got sorted.

Sent from my SM-G965F (S9+)