Key battery

[Deancooper]

Hi,
I have just had notification on the cockpit display saying that key battery needs replacing (golf mk8 keyless ignition). Do I have to get the battery replaced by a VW dealer, not sure if it will need reprogramming when the battery is replaced.
If I have to get it done at a dealer any idea of costs.
TIA
Dean

 

[CH47AV8R]

Hi,
I have just had notification on the cockpit display saying that key battery needs replacing (golf mk8 keyless ignition). Do I have to get the battery replaced by a VW dealer, not sure if it will need reprogramming when the battery is replaced.
If I have to get it done at a dealer any idea of costs.
TIA
Dean

Anyone can replace the battery and no programming of any sort is required.

 

[SRGTD]

There shouldn’t be any need to get the key fob battery replaced by the dealer and no reprogramming required. I replaced mine last year (previous style VW key fob; my car’s a 2020 Polo GTI+ with keyless entry / keyless start/stop). With mine, it was a 2-3 minute job.

Be aware that there are quite a few fake batteries on sale on some well known online websites; IMHO it‘s best to buy new replacements locally so if there’s a problem with them you can take them back in person for an exchange or a refund. Also, make sure any new batteries are a reputable brand with a long shelf life.

Here‘s a couple of links to YouTube videos showing how to change the battery in the newer style (slimline piano black) key fob like the one used by the mk8 Golf. Be careful removing the cover off the casing so you don’t break any of the (rather flimsy) clips on the back of the cover that hold it in place. Also, make sure you remove the correct side of the casing to access the battery - if the incorrect side of the casing is removed, it can be very difficult to re-fit it back into place.

 

[orlinst]

I had the same message and changed the battery. I tested the old one and it was ok - it was about 1 year old. Now, with the new one, the message still apears on every start. So you can replace it and check the old one just in case.

 

[CH47AV8R]

I had the same message and changed the battery. I tested the old one and it was ok - it was about 1 year old. Now, with the new one, the message still apears on every start. So you can replace it and check the old one just in case.

Just measuring voltage with a generic multimeter doesn't really give a good indication of whether a cell is serviceable.
All batteries really need to be tested under load to determine state of charge/serviceability.

 

[keith1200rs]

You cannot really load a CR2032 much - 1mA maximum, from memory. What voltage did you measure? Lithium button cells start at over 3.3V and some devices throw up a warning at 3V.

 

[CH47AV8R]

TLDW; with 4.7kΩ load - if V > 2.8V cell is good. V < 2.8V - discard cell.

 

[orlinst]

Anyway, my point was that even with brand new battery the message still appears. So maybe there is some sw issue.

 

[p.eTSI]

We have had this msg for both fobs, 12 months into new car ownership.

Now at the 24 month mark, both fobs are being requested for new batteries again.

Eating through those cells far quicker than anticipated.

 

[SRGTD]

We have had this msg for both fobs, 12 months into new car ownership.

Now at the 24 month mark, both fobs are being requested for new batteries again.

Eating through those cells far quicker than anticipated.

If you have keyless entry, then if owner’s experience of the previous generation Golf with keyless entry is also typical of the mk8 key fob battery life (I don’t know if it is), 12 months fob battery lifespan isn’t unusual.

My car (a 2020 Polo GTI+) has keyless entry / keyless start - something I would never never have optioned but It was part of the car’s standard spec. I always disable the keyless entry function each time I lock the car and doing so means the key fob and car aren’t communicating with each other. My fob battery lasted 2 years before I got the message in the instrument display to change the battery. Interestingly, I’ve never had to change a fob battery in any of the previous four VW’s I owned (none had keyless entry), and I owned each of those cars between 4 and 5 years.

 

[p.eTSI]

If you have keyless entry, then if owner’s experience of the previous generation Golf with keyless entry is also typical of the mk8 key fob battery life (I don’t know if it is), 12 months fob battery lifespan isn’t unusual.

My car (a 2020 Polo GTI+) has keyless entry / keyless start - something I would never never have optioned but It was part of the car’s standard spec. I always disable the keyless entry function each time I lock the car and doing so means the key fob and car aren’t communicating with each other. My fob battery lasted 2 years before I got the message in the instrument display to change the battery. Interestingly, I’ve never had to change a fob battery in any of the previous four VW’s I owned (none had keyless entry), and I owned each of those cars between 4 and 5 years.

We turned off the proximity unlocking function almost immediately after picking the car up. It was far too annoying, the car locking/unlocking itself anytime you were in close by (also because, like you, we didn't want the fob transmitting signal all the time). Appreciate this is the designed function but it was too annoying and also, for us, posed a security risk (i.e. somebody else could get in the car if we were closeby). We have been happy with keeping the fob on us, and using the 'touch' controls on the door handle to lock/unlock.

Despite the above, the fob batteries have only lasted 12 months.
Maybe, as you say, its the expected lifespan. Which is pretty poor.

 

[CH47AV8R]

We have had this msg for both fobs, 12 months into new car ownership.

Now at the 24 month mark, both fobs are being requested for new batteries again.

Eating through those cells far quicker than anticipated.

If you have keyless entry, then if owner’s experience of the previous generation Golf with keyless entry is also typical of the mk8 key fob battery life (I don’t know if it is), 12 months fob battery lifespan isn’t unusual.

My car (a 2020 Polo GTI+) has keyless entry / keyless start - something I would never never have optioned but It was part of the car’s standard spec. I always disable the keyless entry function each time I lock the car and doing so means the key fob and car aren’t communicating with each other. My fob battery lasted 2 years before I got the message in the instrument display to change the battery. Interestingly, I’ve never had to change a fob battery in any of the previous four VW’s I owned (none had keyless entry), and I owned each of those cars between 4 and 5 years.

This is why there are CR2032s in my glovebox.

 

[keith1200rs]

I am not surprised the batteries have a short life - whenever my key moves the light flashes and I presume it is looking for the car, even if I'm nowhere near it.

 

[SRGTD]

This is why there are CR2032s in my glovebox.

I also keep spare fob batteries in my car and in my wallet.

 

[Genegenie]

I buy my CR2032's from poundland-type shops, 6 for a quid - bargain, they don't last any longer or shorter (3, 6, 12 months, whatever) than 2 for £4.99 apparent 'quality' batteries from supermarkets, photoshops, etc....