I want to carry a spare key fob battery, I have read somewhere that it is a CR 2032, but some times a different one is used? My key fob is the one where the physical key pulls out, i.e. not hinged. 2025 sportsline.,

For your own peace of mind, maybe just open up the key body - no doubt Google will show you how, and check what is written on the exposed face of the battery - you should not need to remove it from this version of the key fob, so no need to worry about anything going wrong.

Unlike the 2 guides that I've just watched, I prefer to use a kitchen-table knife to prise open the key body, I'd rather use that than damage/bend the other key's blade!

Now, VW Group always only fit Panasonic batteries, so I've always only ever bought and fitted Panasonic batteries bought online from sources that seem to sell genuine batteries and always show a picture so that you know the "use by" date of what you are buying.

Screwfix I find to be a good source for remote key batteries, usually Varta. Seem to last as long as any others.

There have been several conversations on this topic. The concensus is that Panasonic is a good choice. I always use them. Others may work, but they may not. I always keep a Panasonic in the car and another in my wallet just in case. My daughter has a Captur and that wouldn't work until I used a Panasonic.

Thank you

The original batteries for my 2018 Karoq were Panasonic, in my case 2025, so I have always used Panasonic as replacements. They can last for 2 years but I did have one that only lasted for 3 months, so there is some product variability.

I tend to stick to one key fob because it's got a load of other keys attached to the key ring but it is important to remember to change the battery in the spare fob at the same time as changing the battery in the main fob.

AFAIK, habitually using only one key fob can lead to issues where the unused fob gets 'out of sync' with the immobiliser rolling code.

5 hours ago, Warrior193 said:

AFAIK, habitually using only one key fob can lead to issues where the unused fob gets 'out of sync' with the immobiliser rolling code.

Thanks for making that point - I must bear it in mind. I've not experienced any problems, but then, my wife does occasionally use the 'spare' key for when, say, we take the car into town and she gets back to the car before me.

What would be the result of the key being 'out of synch', and can it be remedied by the owner ......... or, is it a sucks air through the teeth main dealer job?

Thanks.

If the key fob loses sync, it becomes inoperative until it is resynced.

I always rotate the spare fobs on both our vehicles, so have never had to do it - but I think I have seen references to some procedure using the emergency lock cylinder to unlock, then starting the vehicle within a short time period.