Does anyone know anything about key unlock/lock synchronisations? When I was at the stealer a few months ago, I overhead one of the service advisors on the phone telling someone that if one key is used say 1000 times, then the spare on 40 uses can fall out of sync - something to do with codes.

 

I'd never heard of this before, but wondered if anyone else might know? I have three keys (my main, a spare and then one that lives in the safe), with the main being used several times a day, the spare every month or so and then never the third one. I can't really be bothered to swap keys (I have a special vRS end tip on my main!) but will do if it means not having to deal with any key issues.

My understanding is that the keyfob sends a rolling code signal - meaning that a different code is sent each time the vehicle is unlocked.

AFAIK, the receiver has a list of expected codes to recognise - or anticipate in subsequent code sequences, which change every time the RX & TX communicate.

It is apparently possible for the transmitter and receiver codes to become mis-matched if the transmitter sends more than a certain number of codes while not in range of the receiver.     

I used the the one key for five years .  Have now replaced Octavia with newer model.  

@jazzyjeff did you ever try the other key (e.g. when you sold it)?

 

I've never had an issue with keys before, but I got caught out with the whole 'due to ODIS a normal garage can't code in your new battery, Sir' and didn't want to make a similar mistake again!

If the keys become mismatched, unlock the car with a working key, then turn on ignition with the non working key and that often resolves the issue. If it is still not resolved, press a button on the non-working key, e.g door open button, and keep it pressed for a while until the car can match the sequence being sent.

Of course with Kessy, turning on ignition with a different key becomes problematic, but you could try e.g. pressing door open/close button on the problematic keycard (once the car is unlocked with the functioning key).

 

In theory, you can also match keys on a locked car by pressing the door open button on the key for long enough, but to be honest this has never worked out for me, so cannot say for sure.

I have had mismatched keys a couple times in the past on 2 cars, once because of not using one key for many years, and another time after replacing the keyfob battery. 

In general, a lot of things requiring security code tend to resolve themselves or at least are much easier to resolve once ignition is on, not just keyfob issues but also e.g. radio code issues.

 

I never did try the third spare key, so cannot say if any issues after new owner took delivery.  

@Warrior193 @dieselV6

 

Regarding sequenced keys/codes - do either of you know if using a spare key 'brings it up to speed' with the car/rx? I.E. in theory, using the spare key(s) to unlock and lock the car every few months should keep things working?

I've heard that if you physically unlock the car with the spare key then put it in the ignition and press the unlock button it will resync the rolling code?

1 hour ago, Occy245 said:

@Warrior193 @dieselV6

 

Regarding sequenced keys/codes - do either of you know if using a spare key 'brings it up to speed' with the car/rx? I.E. in theory, using the spare key(s) to unlock and lock the car every few months should keep things working?

Yes, I believe that this is the recommended practice.

51 minutes ago, PetrolDave said:

I've heard that if you physically unlock the car with the spare key then put it in the ignition and press the unlock button it will resync the rolling code?

It is probably not necessary to do that if the spare key has been accepted to unlock the car, I'd have thought the rolling code would have updated on unlocking.

55 minutes ago, PetrolDave said:

I've heard that if you physically unlock the car with the spare key then put it in the ignition and press the unlock button it will resync the rolling code?

Do you mean unlock with the emergency lock?

3 hours ago, PetrolDave said:

I've heard that if you physically unlock the car with the spare key then put it in the ignition and press the unlock button it will resync the rolling code?

 

2 hours ago, Warrior193 said:

It is probably not necessary to do that if the spare key has been accepted to unlock the car, I'd have thought the rolling code would have updated on unlocking.

Note I said physically unlock (i.e. by sliding the cover on the door handle and using the actual physical key) this is for when the remote doesn't work.

Quick update to this thread, as I got my ‘new’ car today and when I got home, I found that one remote key didn’t work. The working key was very shiny and well worn, whereas the other one looked like it had never been used. 
 

I first replaced the battery, but no joy. I then found this thread, which gave me a few pointers, but I also had a look in the driver’s handbook and found the key synchronisation procedure. 
 

Remove the cover from the lock cylinder on the driver’s door, press one of the buttons on the key, then unlock the door within one minute. When I opened the door, the alarm went off, so I shut the door again, locked and unlocked with the remote and it all works. 👍

Edited 1 February, 20251 yr by daveo138