Remote key matching

[maclee]

1999/2000 SEAT Toledo, (same sort of age at the B5/B5.5 Passat).

I need the advice of a professor of keys!!

A few weeks ago, while away on holiday, the remote function of the (one) remote key stopped working.

This did not and does not affect the immobiliser... everything works fine with the key blade.

Assuming this to be a dead fob battery, I bought a replacement, & matched the key to the car in the usual way, (turn the key to the locked position and press the lock button on the remote).

This worked fine for a couple of days then it again failed to work. I noticed that the fob LED only flashed for a few button presses, then stopped, so assumed the new battery was perhaps not as good as it could be, (it was inexpensive), so I left it all until returning home.

Since then, I have fitted another, brand new battery from a local supermarket, but it still would not match to the car, and the LED still only flashed for a few button presses.

I bought a secondhand key from ebay, but despite the LED working on this one as it should, I still could not pair it to the car. I then discovered that the car is probably programmed to accept only one remote key, so I sent the original for repair to a repair service with an excellent reputation, and it was returned promptly. The LED now flashes as it should, but the key will still not be recognised by the car, despite me following all the methods of pairing that I found on Youtube.

I suspect that the CCM has somehow lost its ability to recognise the original key as well as being unable to recognise the second hand one I bought.

My local, tame and very competent mechanic has tried to help, but has a generic computer which, although brilliant for almost everything he encounters, does not follow the same process as is described on line, (for example in the Ross-Tech VCDS documents).

I cannot try the free Ross Tech software as it requires a Windows computer, which I do not have.

The car is still usable (with the blade keys), and I am reluctant to go any further in case I somehow manage to screw up the car's ability to see the immobiliser, which would be a bit of a disaster.

It is not essential, but I would like to have the remote key working again, so if there is anyone here who can offer any assistance I would be most grateful.

Thanks