UK-POLOS.NET - THE VW Polo Forum

Hi All, first post here, so new to this forum, no stranger to places like this

I've had a search but cant find anything on here about "key batt" error on the dash. I just bought a 2010 1.4 Polo for my son, he is taking lessons so will be his when he passes soon. Insurance woes to be covered at a later date....!

I've replaced the batteries in both key fobs with Duracell CR2032, both keys displayed the message so I figure its not the key, but something either the key connects to physically to measure the battery key voltage, or I am barking up the wrong tree and its nothing at all to do with the key but main battery?

Any suggestions?

Cheers!

I'd guess, but only guess, that when the car's imob system "talks" to the key, it can work out if the key battery is low by the way the key's signal is received by the car's imob system as there will be an aerial around the ignition key switch that "picks up" the signal from the key's transponder.

I have always trusted Duracell as a battery brand for most uses, but NEVER for VW Group car smart keys, VW Group only ever fit Panasonic at the factory, so that is what I always do, replacing them every maybe 6 years on cars with a basic system, ie without Kessy!

Cheers, I'll try Panasonic. Its a rectangular fob with a button that flips out a metal bit like an old style key. Ta.

Should be getting the info off signal strength, I think. Don't think it's measuring anything through the key itself; they're not connected in that way.

I'm on my 2nd battery in about 3 years. I keep spare Energizer coil cell in my laptop bag.

The low battery warning has always gone away after the battery swap though so not sure why your's would still be reporting it.
As mentioned, try a different brand like the Panasonic. It could just be that. Not all batteries are created equal.

Maybe the Note on this image will help.



I had to change the battery in our Golf's remote control and the only one that worked and works correctly is the Panasonic.

The strange thing is that our 6R is more than 11 years old and I have never had to change the remote control battery. I guess I'll get the message on the multifunction display soon.

@Maccers; also it’s not unusual for online sellers to be selling fake batteries and passing them off as the genuine article. Something to bear in mind if you bought your replacement key fob batteries online.

IMHO it’s worth buying replacement key fob batteries locally; that way you can ensure they have a good expiry date, and if they don’t work you can take them back to the shop you bought them from and ask for new ones.

Thanks for that, the glovebox hand book does not mention to push a button before the swap.

I got the batteries from local Sainsbury, but have just ordered two Panasonic from Amazon. Will see what happens.

Pressing of the button just gets rid of any capacitance in the remote that might still be powering it.
I suppose it must have quite a bit in order to boost the signal.

Did anybody manage a fix for the 'key bat' message?
Tried all what was suggested on here, still have the error message.

Just replaced 4 batteries in 2 sets of VW keys, Polo & Tiguan, as the Tiguan was giving a low battery warning. Used Panasonic batteries. No problem since.

Finally managed to get the 'key bat' message to go away.
After replacing both key batteries and scanning with VCDS with no success, it was disconnected the battery
for a couple of minutes that finally stopped the error message from displaying.

Was it CR2032 that you used? Nothing listed in my manual. Just says take to a dealership haha.

I tried CR2016 duracell as that was what was in I think and they didn't work. Tried a CR2032 duracell and it seems to be too thick and bounces out.

I tried a no brand CR2016 and that is working fine. 2016 polo 1.2

Cheers

The old battery in my fob was Panasonic CR2025 (2.5 mm thick). I had a new CR2032 to hand and tried that, but at 3.2 mm thick it was really too thick to fit properly. Bought a Panasonic CR2025 and everything was sweetness and light again. This was 2 years ago, and still going strong.

Cheers for that