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Model specific boards => Golf mk7 => Topic started by: pixelcellar on 22 February 2023, 12:18

Title: Key Fob Re-Pairing
Post by: pixelcellar on 22 February 2023, 12:18
I've just come to change the battery on one of my key fobs (I only ever use one) and it now doesn't unlock the vehicle. The 'spare' does but I want to make sure both work.

It's a brand new 2025 battery as required, even tried putting the old one back in which wasn't completely dead (car advised changing though) and still no joy.

Seen a few options around on the internet to 're-pair' the key to the car but none have worked, not sure if they are relevant for my model so could just be old info.

It's a Mk7.5 PP 3 Door Manual GTI fyi.

Any help appreciated so I don't get shafted by the dealers!
Title: Re: Key Fob Re-Pairing
Post by: bogwoppit on 22 February 2023, 12:26
Assuming the battery you've changed isn't a dud, have you tried re-syncing the key?

(https://i.postimg.cc/zBnMBSnm/synch.jpg) (https://postimages.org/)
Title: Re: Key Fob Re-Pairing
Post by: pixelcellar on 22 February 2023, 12:33
Ok, just tried that, alarm went off, put key in and turned ignition, no joy. The key light doesn't light either, would be odd if both the existing battery (which was still working in the fob till I swopped it) and the new one were now dead, the one I put isn't that old either as I use the same type for heart rate monitors.

Should the key red led light if there is power regardless of if its paired do you know?
Title: Re: Key Fob Re-Pairing
Post by: bogwoppit on 22 February 2023, 13:14
Yes, I'm going off memory here, but the fob should light up when you press the button, regardless if it's synchronised or not.
You can see it on these 2 videos, before the key is synchronised:

https://www.youtube.com/watch?v=yJqpajzfuEM&t=143s

https://www.youtube.com/watch?v=lb0UdmAVmz4


Title: Re: Key Fob Re-Pairing
Post by: pixelcellar on 22 February 2023, 13:15
Ok, right will try again tomorrow when new batteries arrive as thats got to be the issue then if the red led should light regardless.
Title: Re: Key Fob Re-Pairing
Post by: madstaff on 22 February 2023, 13:33
I had this same problem and it was the crappy batteries off ebay, think your getting a bargain buying a strip of 10 - probably fake GP Lithium as half of them were dead when tested.

Just grabbed some from Screwfix, Varta CR2025 twin pack cost about £2-50 IIRC.
Title: Re: Key Fob Re-Pairing
Post by: EB2019 on 22 February 2023, 15:45
if its possible to mess up, did put the battery in the right way up?

Title: Re: Key Fob Re-Pairing
Post by: pixelcellar on 22 February 2023, 15:58
if its possible to mess up, did put the battery in the right way up?

Lol, yeah even my non technical skills figured that out.... Hoping its just the battery though odd both the original and new ones are completely dead...
Title: Re: Key Fob Re-Pairing
Post by: joe6 on 22 February 2023, 19:14
Had the same problem when changing to a cheap battery. Went dead after about 3 days and showed 0.6v on the multimeter. Worked fine with a new battery without resyncing.
Title: Re: Key Fob Re-Pairing
Post by: Vwjap on 23 February 2023, 11:45
2032 fits aswell 😂,
Title: Re: Key Fob Re-Pairing
Post by: Lordie on 23 February 2023, 15:54
I had the same issue and it was the battery. Tried a different brand and it worked fine
Title: Re: Key Fob Re-Pairing
Post by: pixelcellar on 23 February 2023, 19:38
Batteries just turned up, Energizer Lithium 2025, put one in worked straight away, no re-pairing required despite being powerless for over 24hrs!

Odd that the battery I had in the drawer, still sealed etc wasn't up to it, wasn't even out of date or anything but clearly was dead. That was an Energizer (non lithium) one too!!

Least they'll be a nice post here for people to search in the future for assistance, thanks to all that replied :-)
Title: Re: Key Fob Re-Pairing
Post by: Vwjap on 23 February 2023, 22:15
There’s alot of fakes around dude, (pound shops, eBay)
Title: Re: Key Fob Re-Pairing
Post by: joe6 on 24 February 2023, 18:45
I found the hyundai ones to be reliable - eventually.