Problem with electronic key

Faults and Technical chat for the CUPRA Born
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leonardclenin
Posts: 1
Joined: Wed Jun 05, 2024 4:58 am

Post by leonardclenin »

In some cases, I cannot unlock the car remotely with the key fob. I don't think the problem is with the battery in the key fob, because when I opened the driver's door with the regular key and opened the door, the alarm went off again. After turning off and closing the door, the electronic key works normally.

Does anyone have a similar situation as me? Thank.

Elea4
Posts: 205
Joined: Fri Jun 10, 2022 5:19 pm

Post by Elea4 »

Does your key fob have the special carbon fiber cover? If so, try swapping it with the regular plastic cover.

Carbon fiber can act like a Faraday cage and block EMF signals :roll: :roll: :roll: :roll:

If you don't want to swap covers, you can try rotating the carbon fiber side away from the vehicle when trying to lock/unlock it.
alanjs
Posts: 159
Joined: Mon Jun 27, 2022 3:14 pm

Post by alanjs »

Elea4 wrote: Fri Jun 07, 2024 6:43 pm Does your key fob have the special carbon fiber cover? If so, try swapping it with the regular plastic cover.

Carbon fiber can act like a Faraday cage and block EMF signals :roll: :roll: :roll: :roll:

If you don't want to swap covers, you can try rotating the carbon fiber side away from the vehicle when trying to lock/unlock it.
That's interesting. Can you provide an evidence-based reference or did you "just read somewhere....".
I'm not disputing your statement but I've had the carbon fibre cover on my key fob, no carbon fibre on my wife's key fob since new, and for the last 18 months I've not had any problems but my wife has had a couple of times when the KESSY didn't work first time.
Born V3, Aurora Blue, Tech (M) pack, Firestorm wheels, Pano roof
Ordered 21 June, 2022, delivered 17 Jan 2023
Elea4
Posts: 205
Joined: Fri Jun 10, 2022 5:19 pm

Post by Elea4 »

alanjs wrote: Sat Jun 08, 2024 8:59 am
Elea4 wrote: Fri Jun 07, 2024 6:43 pm Does your key fob have the special carbon fiber cover? If so, try swapping it with the regular plastic cover.

Carbon fiber can act like a Faraday cage and block EMF signals :roll: :roll: :roll: :roll:

If you don't want to swap covers, you can try rotating the carbon fiber side away from the vehicle when trying to lock/unlock it.
That's interesting. Can you provide an evidence-based reference or did you "just read somewhere....".
I'm not disputing your statement but I've had the carbon fibre cover on my key fob, no carbon fibre on my wife's key fob since new, and for the last 18 months I've not had any problems but my wife has had a couple of times when the KESSY didn't work first time.
Evidence based? Sure, there are many scientific publications which discuss the ability of carbon fiber to attenuate EMF:

https://www.sciencedirect.com/science/a ... 6818343762

As for this impacting the Born, this has been discussed on the German Born forum. Take 2 fobs (ideally with fresh batteries) - one with the carbon fiber "member" cover and one without. Then see how far away from your Born that you can lock/unlock it with each fob. Try rotating the fob with the carbon fiber so it either faces the Born or doesn't.

There have been several reports of reduced range presumably due to the carbon fiber cover.

That said, issues with Kessy Advanced are a different kettle of fish and unfortunately very common. Kessy is VAG's UWB fob communication system - while Kessy Advanced has the added radio hardware which allows for automatic un/locking.

Check out the various threads here regarding Kessy Advanced's occasional unreliability.
alanjs
Posts: 159
Joined: Mon Jun 27, 2022 3:14 pm

Post by alanjs »

Elea4 wrote: Sat Jun 08, 2024 10:48 am
Evidence based? Sure, there are many scientific publications which discuss the ability of carbon fiber to attenuate EMF:

https://www.sciencedirect.com/science/a ... 6818343762

As for this impacting the Born, this has been discussed on the German Born forum. Take 2 fobs (ideally with fresh batteries) - one with the carbon fiber "member" cover and one without. Then see how far away from your Born that you can lock/unlock it with each fob. Try rotating the fob with the carbon fiber so it either faces the Born or doesn't.

There have been several reports of reduced range presumably due to the carbon fiber cover.

That said, issues with Kessy Advanced are a different kettle of fish and unfortunately very common. Kessy is VAG's UWB fob communication system - while Kessy Advanced has the added radio hardware which allows for automatic un/locking.

Check out the various threads here regarding Kessy Advanced's occasional unreliability.
OK, thanks for the reference. I'm afraid it's a bit specialised for me to fully understand. I did realise that carbon fibre would have some shielding properties but the fob cover is very thin so I didn't expect it to have a significant effect.
My own experience is that it still functions well enough to lock/unlock using the buttons at 5 or 6 metres away and even works when the car is in the garage and I'm inside the house. Obvously I haven't tested KESSY under those circumstances.
I am very aware of other threads on here with regard to KESSY but I don't check the German forum.
Anyway, it's always interesting to read useful information. Every day is a school day!
Born V3, Aurora Blue, Tech (M) pack, Firestorm wheels, Pano roof
Ordered 21 June, 2022, delivered 17 Jan 2023
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