My Parking Sensors have stopped working - and for the Wife’s sake I need to try and get them fixed.

Anyway - When I engage into Reverse gear I get a constant beep for a couple of seconds from the rear. The Parking Sensor indicator lights up and flashes however no response to obstacles.

The sensors are clean and don’t appear damaged at all.

I am now outside of warranty, on eBay its possible to buy replacement sensors for about £10 ($14USD) but in terms of DIY fix it appears to be a big job?

In terms of
Which Sensor?
How to remove the sensor and check its working?

Is it worth attempting a DIY fix or should I send it to the stealer? Anyone know how much I would be looking to pay - assuming its just a sensor that’s broke?

Any tips?

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3.0D Sport Auto, CARBON BLACK! Grey Leather, Smokey Grey Trim, Running boards, auto dim folding mirrors. 6 Disc CD Changer. Tinted windows. 19" style 132 Wheels. PDC.
Sports Pack. 6 Speed Steptronic. Communications Pack - SATNav MKIV, Digital Television tuner with Teletext.