Spare key not working and won't resync

Feb 17, 2023
5
0
Hello everyone,

My spare key has stopped working. The LED lights up and I'm confident it's not a flat battery. I've tried to resync it following the instructions in the owner's manual but it still doesn't work. The car won't unlock or lock if you press anything on the fob and keyless entry doesn't work. The alarm also goes off if unlocked via the key blade.

My main key works fine, unlocking and locking the car via the buttons and keyless entry.

Does anyone have any ideas how to resync the spare fob or it will be another trip to the dealer?

Thanks
 

SRGTD

Active Member
May 26, 2014
2,363
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Even if you’re pretty confident the battery in your spare key fob isn’t the issue, if I was you I’d swap the battery over from your main key fob to see if the spare fob then works. If it does, then a replacement battery should provide a fix.

If / when buying new fob batteries, be aware that there are lots of fakes out there, so IMHO it’s best to buy replacement batteries (check they have a good expiry date) from a reputable local supplier so if there is an issue, then it’s easy to get the batteries exchanged.
 
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Feb 17, 2023
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Even if you’re pretty confident the battery in your spare key fob isn’t the issue, if I was you I’d swap the battery over from your main key fob to see if the spare fob then works. If it does, then a replacement battery should provide a fix.

If / when buying new fob batteries, be aware that there are lots of fakes out there, so IMHO it’s best to buy replacement batteries (check they have a good expiry date) from a reputable local supplier so if there is an issue, then it’s easy to get the batteries exchanged.
Finally got around to sorting this with a new battery (I'm happy it's genuine) as my main fob is saying the battery needs replacing.

The spare key still won't synchronise.

Anyone got any advice or am I going to have to make yet another trip to the dealer.
 

DEAN0

Old Git
Feb 1, 2006
5,282
298
Preston - UK
Finally got around to sorting this with a new battery (I'm happy it's genuine) as my main fob is saying the battery needs replacing.

The spare key still won't synchronise.

Anyone got any advice or am I going to have to make yet another trip to the dealer.
Check you have the new battery the correct way up in the key fob - yes I have done it !!!!!!!!
 
Feb 17, 2023
5
0
Check you have the new battery the correct way up in the key fob - yes I have done it !!!!!!!!
It's the right way up, fob lights up and everything.

I have tried so far:-

Make sure the working fob is away from the car.

Pressing unlock with the key fob at the door then unlocking with the blade. Alarm goes off.
Having someone sit in the car with the key fob placed in the key slot near the gear selection, pressing unlock then using the blade to unlock the car. Alarm goes off
Sitting in the car with the window down, pressing unlock on the fob then unlocking with the blade and the alarm still goes off.

In all cases trying to start the car with the spare key results in a "Key not detected" message.

I'm getting a bit worried that if I change the main key battery and that too does not work then I'll have to ring Driver Line and the AA will be out...
 

DEAN0

Old Git
Feb 1, 2006
5,282
298
Preston - UK
It's the right way up, fob lights up and everything.

I have tried so far:-

Make sure the working fob is away from the car.

Pressing unlock with the key fob at the door then unlocking with the blade. Alarm goes off.
Having someone sit in the car with the key fob placed in the key slot near the gear selection, pressing unlock then using the blade to unlock the car. Alarm goes off
Sitting in the car with the window down, pressing unlock on the fob then unlocking with the blade and the alarm still goes off.

In all cases trying to start the car with the spare key results in a "Key not detected" message.

I'm getting a bit worried that if I change the main key battery and that too does not work then I'll have to ring Driver Line and the AA will be out...
The book says :


If the "unlock" button is pressed frequently outside of the vehicle range,
it is possible that the vehicle can no longer be locked or unlocked using the key.

In this case, the key must be resynchronised as described below :

Remove the key blade from the vehicle key

Press the "unlock" button on the key - for this, it must remain with the vehicle.

Open the vehicle within one minute using the key blade.
The key has been synchronised.
 

Tell

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Suppose to be anti child bite applied to some of these batteries so they don't swallow them. Duracell ones are said to be coated with this and give you problems with the contacts. I've had issues with Duracell button batteries but not in the car remote (Nvidia remote... gone back to using the old ones, same battery model thou).

Obviously swapping the battery between the good and bad one is a check, but may be it's started to be re-programmed and failed. It may very well be a failed remote control. I think new batteries can sometimes run high which then give you issues.
 
Sep 14, 2023
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I’m having issues with mine. I can use keyless access but I’m not able to unlock and lock the car with the key fob. Let me know how you get on!
 

martin j.

Active Member
Feb 11, 2007
1,994
889
Fife
I seem to remember sales staff when collecting their car to alternate use between keys, if left sitting unused key could loose the programming and both keys then need re synchronised with a new code.
 
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Tell

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The re synch stuff doesnt work these days as a security measure. Only the dealer can program a key. Did I conjure up @East Yorkshire Retrofits .... I recall they confirmed this last time it came up. Older Seats were like this but newer ones like the Ateca don't, ditto Formentor. Thus buying keys off eBay etc doesn't get you anywhere.

The battery goes flat. The programming stays in the memory. The old model. Battery goes flat and you reprogrammed them by holding them close pressing buttons.

I'm sure many Kessy issues are where people fiddle with the programming of Kessy using one click apps. There are a group of people that think its cool for your car to auto lock as you walk away. That assumes Kessy works 100% Ok. It doesn't in some instances and that's when it locks the key in the car. Auto lock with that and the keys locked inside. Antenna not picking up the presence of the key in the car.

Second hand cars you don't know whether Kessy has been hacked to behave in auto mode locking or someone has fumbled the coding of it or a one click app. Why you shouldn't use one click apps but programming so it's transparent what the coding is.

As far as the Formentor is concerned early models were shipped with Kessy issues. Kessy is designed so the handles go to sleep to save power. The drivers side isn't suppose to. They shipped early models where both sides went into power saving mode. There is an emergency blade you can get into the lock and put the alarm off. Never had to.

If Kessy isn't fiddled with it works well.
 
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