Definitive remote fob fix?

[melat0nin]

Hi all

I've read lots of threads about fixing the remote fob, and tried the various remapping procedures, but all to no avail, and I'd like to fix it once and for all (new keys if need be).

I can't tell from my current key what model it is, as all text has been rubbed off it. It's one of the older style ones (I think) that doesn't fold and has two buttons. I can't add a pic because I don't have enough posts on the forum yet.

I have the spare. What do I need to do to get this working? I'm happy to buy new if necessary.

Any help appreciated as it's been driving me nuts!

 

[Sam]

As odd as it may sound, but I'm sure many people have done this without thinking, have you made sure all the correct electronics are in the key? As far as I'm aware, the remapping procedures should work if done correctly, although I've not had the opportunity to test them, yet. If not, then VagCom may possibly have the answer, but don't quote me on this, it'd be best to speak to a VagCom Guru on that matter!

 

[melat0nin]

As odd as it may sound, but I'm sure many people have done this without thinking, have you made sure all the correct electronics are in the key? As far as I'm aware, the remapping procedures should work if done correctly, although I've not had the opportunity to test them, yet. If not, then VagCom may possibly have the answer, but don't quote me on this, it'd be best to speak to a VagCom Guru on that matter!

Thanks for your reply! The key does look like it's been through the wars a bit. The pcb is definitely there and looks intact, and the wee RFID crystal is too. I use the key to start the car, so I'm assuming the problem is with the PCB and not the crystal (am I right in thinking the crystal is part of the immobiliser, so needs to be present in order for the car to start at all?)

 

[Arkaig]

Whats the problem with the key and what do you mean by remapping? Is it to get the fob buttons to unlock the central locking?

If the procedure to pair the remote buttons with the car isn't working, it may be that the microswitches are broken. Does the key flash a red light when you press a button?

If you're up for a bit of soldering then the microswitches can be had for a couple of pounds off ebay.

 

[melat0nin]

Whats the problem with the key and what do you mean by remapping? Is it to get the fob buttons to unlock the central locking?

If the procedure to pair the remote buttons with the car isn't working, it may be that the microswitches are broken. Does the key flash a red light when you press a button?

If you're up for a bit of soldering then the microswitches can be had for a couple of pounds off ebay.

I think the problem might be with the buttons. The lights do flash, but weirdly just now when I pressed the lock one it stayed on

By remapping I meant pairing. I've tried numerous versions of that from around the web, but none of them work.

I took the PCB out and the buttons and board look fine. I wonder if it maybe has had some water damage or similar?

Would a solution be to buy a new fob, put the RFID crystal in it, then re-pair?

 

[melat0nin]

The PCB has these numbers on it (I can't post a pic as I don't have enough posts yet):

2407
L01556B
C01556B
735 684-61

I googled them and they do come up on auction sites as a SEAT/Skoda fob. Would it work just to buy one of these, stick the RFID chip in, and pair?

I've seen some threads on this topic which suggest it's much more complicated (model numbers having to match perfectly etc) so I don't want to take the risk without being sure

 

[Arkaig]

If it's had some water damage then the interior of the microswitches might just be corroded or dirty. If a light is sticking on then it sounds like a switch might be gunked up or losing its 'clickiness'.

It might be worth trying to clean them out while on the PCB before you try anything else.

There should be a metal sheath that can be pried off the top of the switch. Under this is a rubber membrane that should come out. Under that should be a round metal dimple that will just fall out. Give everything a good spray with contact cleaner and clean out any gunk inside. Put it all back together the same way.

If the dimple has lost its 'clickiness' (put it on a flat surface and press it) you can sometimes restore it by giving it a tap dead centre with something fine and sharp like a small punch. Just don't overdo it and warp the dimple or poke through it.

 

[Arkaig]

While you have the switch apart you can also test the PCB is behaving normally by bridging the contacts on the inside of the switch with a small screwdriver or similar. If you get weird behaviour then it may be that the rest of the PCB is goosed somehow. On my old style key the red light pulses every 1/2 second or so when a button is held.

 

[Arkaig]

Be careful with moving RFIDs as on some keys they can lose their settings by being disconnected from the battery for too long.

 

[melat0nin]

Be careful with moving RFIDs as on some keys they can lose their settings by being disconnected from the battery for too long.

AFAIK the wee transponder crystal is inert, i.e. not powered, and as long as it is undamaged it should be fine even if the battery in the fob is dead.

I've opened the switches and they look fine and feel clicky, so I don't think the problem is there. Am thinking maybe the PCB is goosed.

Would it work to buy a replacement fob (identical PCB model numbers), put the crystal in, and remap? I can't see an obvious problem with that approach, but