Do keys lose programming when the battery dies?

Zaphan58

Zaphan58

Zaphan58

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30 Nov 2003
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Hi all, quick question. I have a Golf 8, 1 key works fine and the spare has been sat in a draw for a 2 - 3 years and does not work. I have put a fresh battery in it, tried putting the working battery from the main key in and also tried as the manual says and putting the fob in the cup holder (where the key antenna is). Nothing has worked, the light on the fob flashes but it will not lock, unlock or start the car.

VW say the key may need re-programming at a cost of £100. What I don't understand is how a key can lose its programming. I get that the battery was flat but surely the programming is not lost if the battery goes flat? Or does it?
 
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Just tried my spare key, it’s been sat in a drawer for 5 and a half years since I bought the car new. Still works and unlocks and locks the doors.
 
Zaphan58 said:
Hi all, quick question. I have a Golf 8, 1 key works fine and the spare has been sat in a draw for a 2 - 3 years and does not work. I have put a fresh battery in it, tried putting the working battery from the main key in and also tried as the manual says and putting the fob in the cup holder (where the key antenna is). Nothing has worked, the light on the fob flashes but it will not lock, unlock or start the car.

VW say the key may need re-programming at a cost of £100. What I don't understand is how a key can lose its programming. I get that the battery was flat but surely the programming is not lost if the battery goes flat? Or does it?
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Programming is saved in an eeprom within the fob, eeproms do not need battery to maintain data so in theory it should never lose its programming.
 
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I suspect more modern stuff would be ok.

We were recently away and the battery in our food scales died, could not buy any batteries that size and they are important for our kids meals, I knew my focus fob had the same battery so put it in. After being back from holiday put new battery in and was fine.

My old Rover however once it was flat, needed re-syncing to the car once, though if I recall I could do this myself.
 
shifty_uk said:
The keys programming has no correlation to the battery.

That doesn’t explain why it’s still not working though.
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New cars are made so poorly, it wouldn't surprise me if one of the modules in his car wasn't updated to fix a bug. I've a friend who works in automotive industry, I'm not going to go into details, but he regularly has to fly abroad to supervise engineers and fix their f ups. Once there was a situation when they had to reflash 100's of cars to fix a very obvious bug.

Cost cuts, offshoring, tight deadlines, redundancies and poor hardware doesn't help the situation. I use to laugh when people said that car industry is run by accountants, but now I'm starting to see what they meant...
 
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