First time for me, too, Brian. For all 3 ‘8s. I’d get a pack and change them if I were you. Mine worked fine on Wednesday afternoon and nothing at all on Thursday morning. I was at home, so I was able to just swap keys and order the batteries, luckily.

This won't help you but my D4 brought up a dash message about needing to change the keyfob battery. But still worked until I returned home.

Put a new 2032 in and all good.

Ah, put new batteries in and it still doesn’t work! Any thoughts folks?

Will it need to be reprogrammed or is it knackered?

All suggestions welcome!

Check they're inserted correctly and have decent voltage first.

Also, do you have VCDS, if so look for errors on the central locking.

IIRC reprogramming the remotes is pretty simple if you need to.

IIRC its very easy to put them in upside down, as the design of the battery compartment is counter-intuitive. It caught me out the first time.

Otherwise it may just need re-syncing which is pretty simple.

Others have beaten me to it about battery position, but for programming it, see the post by Mark on this same thread:

http://forum.a8parts.co.uk/showpost....5&postcount=11

There is also a link to a YouTube video as well.

Thanks guys and gals!

I checked the voltage after inserting the batteries (6.5V) so I think they’re in the right way, but I’ll check again.

I do have VCDS but, as the other key works fine, I doubt if it a central locking fault.

And the suspect key works fine in the ignition.

So, I’ll check battery orientation and then reprogramme it.

Ignition/immobiliser are totally independent (in the key) of remote unlocking so it should indeed start fine.
Shouldn't need reprogramming after a battery swap, check VCDS first it logs errors by key number.

Checked batteries - in the right way.

Watched the key coding video and noted that it’s quite different to Mark’s instructions!

Followed Mark’s instructions (note: the working key goes into the ignition!) and it worked!

Just going to see what VCDS says.