Hello All,

 

Have two keys, one had low battery and replaced it. After I did so, will open and lock doors but not start the engine “ key not found “

 

Manual states to re-sync press any button on key, then present the key blade to manually unlock the drivers side door <1 minute.

 

Can again open the door with key in question,  (manually),  but still doesn’t sync / start engine.

 

Have now replaced battery on second lesser used key, no issues. So no urgent 

 

However , dealer advise that re-code of original key at £45 is the only solution ?

 

Any comments or advice would be greatly appreciated.

 

Many Thanks,

 

Stevie 

On 12/01/2021 at 12:01, StevieG14 said:

Hello All,

 

Have two keys, one had low battery and replaced it. After I did so, will open and lock doors but not start the engine “ key not found “

 

Manual states to re-sync press any button on key, then present the key blade to manually unlock the drivers side door <1 minute.

 

Can again open the door with key in question,  (manually),  but still doesn’t sync / start engine.

 

Have now replaced battery on second lesser used key, no issues. So no urgent 

 

However , dealer advise that re-code of original key at £45 is the only solution ?

 

Any comments or advice would be greatly appreciated.

 

Many Thanks,

 

Stevie 

Hi Stevie,

 

Did you manage to find a a solution to your key sync issue?

 

 

Well, I can tell you where that crashed n burned twice on my 2017 Fabia:

• Just changing the battery did not allow the fob to operate the doors

• the front doors do not sport mechanical key-locks

I'm sure Skoda saved $10/Fabia by deleting the locks, but it's a bit short-sighted. What happens when the battery fails, or e.g., the interior light is left on, and you can't get into the car to open the bonnet?

1 hour ago, Miikey63 said:

the front doors do not sport mechanical key-locks

Have you had a look at the Owner's Manual for ?Emergency door locking? I'll see i I can find my jpg.

Also see synchronising the remote control -

Found it. Or was this all deleted after 2016?

Edited 25 April, 20251 yr by nta16

If the key isn't being reckognised by the ignition I would suspect a faulty transponder chip in the key. The fact the other one works tells me the reader coil in the ignition etc is working. It may have been damaged somehow or perhaps fallen out when the battery was changed. A decent car locksmith may be able check and copy the chip in the good key for you.

Alasdair

Fallen out? Surely it's soldered to, or due to the high frequency, is part of the PCB.

I find that on my 2019 Fabia, it was intended for the EU and only the passenger side has the cutout to pop the cover off the key barrel. Unfortunately, press a button then unlock didn't cause the ECU to learn my second key.

I’ve had a nightmare with keyfob batteries for the Fabia - even major brands.

Now I always test the new battery before changing. This has been a godsend

Ansmann Alkaline Button Cell & L...

Ansmann Alkaline Button Cell & Lithium Coin Battery Tester

Some of the new batteries were nearly dead.

Mark.

Thanks Mark. I have an EE degree and enough kit to check a new battery. Where it fails for me is the User manual claim that a fully discharged fob will be sync'd with the car if a button is pressed for 10s without battery, then with a new battery, within 8s press any key on the remote.

On 28/10/2025 at 18:18, Miikey63 said:

Fallen out? Surely it's soldered to, or due to the high frequency, is part of the PCB.

I think the part Alasdair is referring to is this, which has no electrical connection to anything in the fob. Known as ID48, "immobiliser chip", or "bugger, that was fragile" depending on the circumstances.

I'm not sure if a 2017 keyfob still has such a device.

Edited 2 November, 20252 Nov by Breezy_Pete

I can tell you exactly what that is. It is the coded chip, and the inductor allows it to receive power from probably a coil around the key barrel under the cowling. When it gets enough power, it transmits its code. We use them at my OEM employer. What amuses me is that it is an Australian design used to count sheep as they are driven through a large inductive loop gateway. Each sheep can be individually logged.

I wasn't asking what it was, I was showing you what Alasdair meant, but which you thought would be soldered to, or part of the PCB.

So look for it in the fob and see whether it looks damaged or absent.

Well, I'm sorry I'm boring you, but I think some readers will find it a fun fact that the security chip in their key was developed by Australian farmers so they could quickly count and register flocks of many hundreds of animals by placing an inductive loop over the gate / sheep dip and then driving the flock through them, with an immediate read-out of any missing animals. I worked with these first in 1992. It charges using inductive loop power like power share or loop charging on a smartphone, or the inductive loop on a Braun electric toothbrush stand. You can't re-program the chip code, but you can re-program the ECU that it's a valid code to operate the car. We distributed validation amongst several ECUs so changing just one wouldn't let the car accept a new key.

I didn't need any violence to get to the point in the picture. Popping the right plastic clip did the job. The spring terminals for the battery don't leave space at that level for the coded chip, but it could be to the left of the positive plate contacts, or under the text where the folded key parks. I don't find any easy clips to pop to get the remaining two halves apart, and I want to keep it in a state where I can re-assemble it into a working key when I'm done as it's a mechanical match to the car. Any help here? the main body looks like two plastic shells clipped together, but unlike e.g., laptops, it's not a case of working around the outside with a plastic lever tool.

I'm pretty sure (but not certain because I can't remember) the back comes off as when I took one apart I lost the spring or spring out effect for the keyblade but like you I want to keep, the much more reliable mechanical, keyblade but I might have a go for you after tea/dinner.

Thanks NTA16. All suggestions gratefully receieved. I can see two <~1mm roll-pins, one holding the mechanical keyway stem, and the other as the pivot point of the spring-loaded mechanical key. It wouldn't be the first thing I've disassembled with the outcome of the neccessary spring escaping somewhere into my office.

56 minutes ago, Miikey63 said:

and the other as the pivot point of the spring-loaded mechanical key

Yeah the second pin must be the bit I lost or couldn't lock last time, I forget, if you loose that you can still operate the fold and unfold of the keyblade but you might need fingernails wot I don't not 'ave much of.

I've just took the spare apart and it was easy (perhaps missing the second roll -pin helps?) I think I pushed on the blade release button and this put enough pressure on the spring under it to show up where the two bit of VW wunderbar fantastic-plastic can be parted using a small (but not tiny or precision blade) blade screwdriver. The board comes out easy (in one piece / not broken).

Whether the bit you want is the white bit on the reverse side to battery I don't know.

If you want I can (try to) take photos of both sides of the board in case things are different between our remotes.

ETA: zooming in on your low-res GIF I think I can see a second spring for the keyblade so perhaps it was that I couldn't locate and/or a second roll-pin, or both.

As you have/will discover you don't need to remove the wunderbar fantastic-plastic Škoda symbol on the remote or the the panel for the three push buttons (pegs) as there's another diagram(?) under them anyway.

Part from the opposite side to the buttons.

Edited 19 November, 202519 Nov by nta16
bold

Hi Nigel,

Yes, I discovered that there's no progress to be had from removing the skoda viking sticker symbol. As I've worked with this transponder before, and the Hella 434MHz matches, I think there are two possible locations. One is under the text label into which the key-stem folds, and the other is top right of the battery positive contacts. I think this second one is more likely. I don't see it falling out past the metal contacts when the battery is swapped as they block this hole well (see second pic). The plastic clip to the top would be a convenient cover to protect the transponder chip.

Sorry I'm lost now as you seem to have two different fobs my wife's car only came with two flick-out keyblade fobs and I assumed that was the way for all.

Bear in mind I have taken my fob apart (ETA: before) but can't remember exactly what I done (other than not being able to fit a spring as possibly I didn't see a second roll pin or the springs proper location and fitment - Sod's Law springs will spring out before you can see where from, and often get lost).

14 minutes ago, Miikey63 said:

One is under the text label into which the key-stem folds

When I took the key apart this time there was nothing under the text label (but there again this fob didn't have a label(!??!).

17 minutes ago, Miikey63 said:

and the other is top right of the battery positive contacts.

The board I have (for the flick-out keyblade remote) looks to me the same as yours and to me it doesn't look like there's anything missing on yours or mine from that side of the board but I know nothing about electronics and I have poor quality eyes (and brain) (I broke off the speaker wire connection on my 2003 DAB radio and can't see on the board where the connection might have been and have to use the additional external plug in speaker to get one-channel stereo).

BTW the (internal) spring for the flip button has a foot at one end only and needs correct location so keep all bits in order and orientation if you remove them (or like me more often drop or knock them to the floor).

If want or need you could take a photo of the other side of the flick-out remote board and I'll see if there are any difference(s) to the one I have.

Edited 22 November, 202522 Nov by nta16
missing word

On 19/11/2025 at 18:21, nta16 said:

Whether the bit you want is the white bit on the reverse side to battery I don't know.

Just picked up one of the working remotes this morning and realise that white bit would be the red conformation light, wasn't even using the remote just putting the keys back in their place, some days and seconds of the say my brain is better than for the rest of the time.

On 19/11/2025 at 18:38, nta16 said:

or the the panel for the three push buttons (pegs) as there's another diagram(?) under them anyway.

Also whilst looking for the quote above I noticed the typos in this and double-word error, should read - ... or the panel for the three push buttons as there's another flexible plastic diaphragm under there anyway.

You probably already knew that but just to clarify for future, teach the AI.😆