Change the key battery!

[varaderoguy]

4 hours ago, TheWanderer said:

it seems that it's not a good idea to put the key on a keyring with other keys as it seems to drain the battery quickly

Yes - but only if those keys also have transponders or transceivers on them.  A standard key or KESSY key just on a key chain shouldn't make any difference.

[TheWanderer]

I've had to change the battery on my keys twice in 2 months and had one key leave me stranded. 

 

The only place it had been is on my carabiner on my belt with door keys. 

[varaderoguy]

1 minute ago, TheWanderer said:

The only place it had been is on my carabiner on my belt with door keys. 

Goodness - BTW - just out of interest (without giving your exact location away); are you near any transmitters or mobile phone masts (or even electrical high voltage power lines??  These may be causing interference.  As a suggestion (and a relatively cheap way of seeing if it is external radio sources causing interference), have you tried getting a Faraday pouch (random link) for your car keys?

[TheWanderer]

At home no. I live about a mile from the nearest phone mast, no powerlines here in the Surrey Hills. 

 

At work gawd knows where they are I know at work we get a pretty good 5G service but that shouldn't have any effect and the stuff I work on is generally old (1982-84 vintage).

 

For now I'm keeping the key in my trousers pocket to see if it makes any difference. 

Edited 4 August, 2021 by TheWanderer

[HandyAntman]

I had an intermittent low Keyfob battery issue. Initially tried three brands of 2025 cell but could only get it to work with a 2032.  I put put this down to cell impedance variations between manufacturers. This lasted about 3 months and then after changing again still gave occasional errors. That was until I had to invoke emergency access procedure in Sainsburys car park one day when the key became dead with no red led.

Changed battery again and key still dead. So I assumed that the key itself was dying and potentially expensive (key plus reprogramming etc).

 

In for a penny, I dismantled as much of the key as possible (not quite sure how to access the pcb entirely which is what I really wanted to do). Then gave all access holes in the key a gentle blow with the airline as there was evidence of dust having got into the key past the seals.

After this the key has worked faultlessly for the last 6 months with the same battery that was supposedly dead.

 

The conculsion I draw is that some dust must have been somehow shorting out the RF or uproc and causing the malfunction. This caused a higher current drain from the battery - meaning only a lower impedance cell (higher current capability)  could drive the circuit until it was prevented from operating completely.

 

So for repeated early low battery failures - try internal cleaning of the pcb.

(OBD11 incidentally only showed the' intermittent key battery' error logged which I reset and has remained clear since.)

 

[EnterName]

14 minutes ago, HandyAntman said:

In for a penny, I dismantled as much of the key as possible (not quite sure how to access the pcb entirely which is what I really wanted to do). Then gave all access holes in the key a gentle blow with the airline as there was evidence of dust having got into the key past the seals.

After this the key has worked faultlessly for the last 6 months with the same battery that was supposedly dead.

 

The conculsion I draw is that some dust must have been somehow shorting out the RF or uproc and causing the malfunction. This caused a higher current drain from the battery - meaning only a lower impedance cell (higher current capability)  could drive the circuit until it was prevented from operating completely.

 

So for repeated early low battery failures - try internal cleaning of the pcb.

(OBD11 incidentally only showed the' intermittent key battery' error logged which I reset and has remained clear since.)

 

Do you have keyless entry on your car, @HandyAntman?

[HandyAntman]

Hi

No not KESSY - too much of a security risk for my liking.

Just standard 3-button button remote and old fahioned ignition key

[Wet Kipper]

I've got a good one. 

Changed the battery in Key 1. It unlocked the car and never flashed again with any button press. 

 key 2, existing (old) battery, works fine.

Swapped batteries round to see if New battery (NB) is faulty.

OB(2) in k1, no flash. NB(1) in K2. Flashed a few times. 

Swapped back.

NB1 in k1 = nothing.

OB2 in k2 = nothing

Uh oh.!

Tried the re-synching from the manual but only succeeded in setting off the alarm from not starting the car soon enough after manually (key in lock) opening the door. 

Thankfully I have a third key, which works fine. But I'm now not sure if the issue is just with the batteries, the keys, or a bit of both

Edited 27 November, 2021 by Wet Kipper

[HandyAntman]

I've come across this with other manufacturers where the voltage partially dies away when the battery is removed but only enough to corrupt the uProc/memory in the key - especally if the battery is swapped too quickly. Then the new battery appears not to work.

I assume you don't have the same problem I did (unlikely with both keys) so try removing the battery and holding down one of the buttons for 15 secs. This will discharge any residual voltage in the key to allow a 'cold boot' when the new battery is inserted.

If the red LED in the keyfob does not flash when a button is pressed then there is definitiely a problem in the key - regardless of whether it is coded to the car or not.

[Wet Kipper]

Thanks, I'll give that a try 

[Baxlin]

Yesterday evening this warning appeared on my Octavia’s screen, so I changed the battery, using a slightly thicker 2032 I had ‘in stock’.  I must say, it’s one of the easiest methods I’ve come across - once I’d found the how-to in the manual, that is...

 

As you do, I picked up my iPad and went to this site - I always “unread content” as one of my favourites, and surprise surprise, there was this thread prominent.  Reading some of the comments, it seems I was lucky in having no problems, everything worked first time.

Edited 29 November, 2021 by Baxlin

[stanian]

On 28/11/2021 at 14:25, HandyAntman said:

I've come across this with other manufacturers where the voltage partially dies away when the battery is removed but only enough to corrupt the uProc/memory in the key - especally if the battery is swapped too quickly. Then the new battery appears not to work.

I assume you don't have the same problem I did (unlikely with both keys) so try removing the battery and holding down one of the buttons for 15 secs. This will discharge any residual voltage in the key to allow a 'cold boot' when the new battery is inserted.

If the red LED in the keyfob does not flash when a button is pressed then there is definitiely a problem in the key - regardless of whether it is coded to the car or not.

Had this issue today, got the "change key battery warning", replaced with brand new voltage checked battery and ......................nothing. Left battery out for 15 secs, pressed button with no battery in fitted and led on key flashed, then replaced the new battery that didnt work first time and it is working fine.

[Wet Kipper]

Didn't seem to help mine so I ended up popping into the dealership to check. Especially as the 3rd key was flashing the warning and I didn't want to kill it too 

Naturally, when they swapped the batteries for some of theirs, it's working magically

Edited 4 December, 2021 by Wet Kipper

[Boola]

I found a solution to this problem. I changed batteries in my key when the change key battery message came up, it was still there so I also changed battery in my other key. Problem was still there. Finally I changed battery in my petreloem warmer, problem still there.

 

Solution:

I found that change key battery message came up because I had different brand of batteries in my three keys. When i put batteries of the brand varta 2032 in all three of them the message dissappeared. I hope this helps some as it was driving me nuts.

[fr1nklyn]

Isn’t the O3 key battery CR2025? Mine is pre-FL model 2016 and when I tried CR2032 battery I noticed that it pushes the plastic too much and causes the chip to bend, that’s why moved back to factory size CR2025.

This could also be the cause for the issues.

[Boola]

56 minutes ago, fr1nklyn said:

Isn’t the O3 key battery CR2025? Mine is pre-FL model 2016 and when I tried CR2032 battery I noticed that it pushes the plastic too much and causes the chip to bend, that’s why moved back to factory size CR2025.

This could also be the cause for the issues.

 

Sorry, i tried this on my Skoda Octavia 2021 (i have one 2020 and one 2021). I saw now that the thread is for 2013-2020 model. But i think it's worth trying the same battery brand in all the batteries as i had this problem in my car. Could be that the old one has CR2025 (i have yet changed my key in my 2020 model yet). But the 2021 model is thirsty as hell with the KESSY system.

[PetrolDave]

2 hours ago, fr1nklyn said:

Isn’t the O3 key battery CR2025? Mine is pre-FL model 2016 and when I tried CR2032 battery I noticed that it pushes the plastic too much and causes the chip to bend, that’s why moved back to factory size CR2025.

This could also be the cause for the issues.

I've used the CR2032 in all 4 fobs from my 2015 and 2016 Octavia 3's with no problems.

[nidza]

I was unable to put fully 2032 battery under this little tooth properly, but it worked, was able to put cover back holding the battery strong enough. Anyway, half-solved isn't my cup of tea, so I've replaced it with 2025 eventually.

[fr1nklyn]

20 hours ago, PetrolDave said:

I've used the CR2032 in all 4 fobs from my 2015 and 2016 Octavia 3's with no problems.

It works but it’s too tight, or I’m overthinking it  

Edited 8 November, 2023 by fr1nklyn