After the car has been in the garage overnight, the car starts normally but when I select reverse, the system beeps normally and the car symbol on the radio shows but after a couple of seconds, there is a longer, higher pitched beep and the car symbol disappears. The reversing lights work normally but there is no audible or visual reverse sensor warning. Usually, after driving for a few miles, the system starts to work normally until the next time it's left overnight.

Is it possible I have a gremlin in my garage that comes out at night and messes with the car?

A wiring diagram of the system would be useful.  ​

+1 here, same issue

There's an old thread on a similar issue that might help:

 

http://www.briskoda.net/forums/topic/178211-parking-sensors/

Mine were working sometimes, not all of the time. Tried cleaning the outside and spraying with electrical contact spray. It didn't make much difference. They were 'sort of' fixed under warranty, they didn't fail quite so much, but still failed occasionally.

 

I recently had a tow bar fitted, and the bumper was removed to fit. My goodness - you should have seen the muck and grit inside the bumper!  While it was off, I cleaned it out and used a hairdryer to dry the little electrical plugs that are fixed to the inside of the bumper that connect to the system.  Hey presto!  My reversing sensors are now working 100% all of the time.

Edited 29 April, 201610 yr by Morgana

I've just taken the bumper off and removed and cleaned all the sensors. It was dry and just a bit dusty inside and all the electrical connections were dry, clean and bright. I'm having problems finding new sensors at a sensible price. I bought a pair from E-bay that were supposed to fit but didn't. The only genuine ones I can find in the UK are over  £50 each. A bit much if the fault is elsewhere. The Part number is 5JO 919 275 so if anyone can find them cheaper or can suggest a possible different fault I'd be grateful.

Hi

 

I tried

5J0 919 275A

May be the same ?

 

£30 from Germany + postage

http://www.ebay.co.uk/itm/Parktronic-PDC-Sensor-Parksensor-fur-Skoda-Fabia-hinten-5J0-919-275-A-NEU-/262281487183

 

£30 from Slovakia (Free postage)

http://www.ebay.co.uk/itm/NEU-Original-Metasystem-PDC-Sensor-Parksensor-fur-Fabia-II-Roomster-5J0919275A-/252351197462

 

Others from Slovakia etc. at similar prices too

http://www.ebay.co.uk/sch/i.html?&_nkw=5J0+919+275A&_sacat=0

 

HTH

I bought one and tried it in all 4 locations but the fault remains. I've just learnt to live with it for now but may have to get a garage to see if the fault is elsewhere.

A VCDS scan will tell you which sensor is the culprit, one dud brings the whole system down. 

 

I have peeled the limo tints off the rear windows for the time being so I can at least sight reverse, I'll have the bumper off in the summer and fix it with shrink wraps on all of the connections to ensure they remain watertight. 

 

I've seen a You Tube clip that says you can hear the good sensors clicking when reverse is engaged - it didn't work for me though

I saw the same clip - couldn't hear them either. Just hoping my local, friendly garages' VCDS can find the problem