how does the car know which key is in the ignition

[nigeldodd]

How does the car know which key is in the ignition? The metal parts look identical. Does it handshake with the electronics?

[Vwjap]

Yep there’s a transponder chip inside (I think it used to be the vw badge on the key, but I am gullible 😉)

[nigeldodd]

So, is it the transponder that provides the real security as opposed to the mechanical profile of the metal part of the key?

[clubsport]

Yes transponder is the security part. I needed a spare key for another VW.

I bought a key blade and had that cut and then bought a seperate key body with transponder inside.

It was unable to start the car until the transponder was programmed to match the car with Vagcom, VCDS etc...

The key worked perfectly for years in my ownership.

[mcmaddy]

You can't code keys with vcds since the MK4 or possibly the mk5.

[fredgroves]

The two keys you have (on a mk7.5) can be assigned to different driver profiles, which have different settings for all sorts of things from bluetooth pairing, to radio presets to various vehicle settings.

The keys have different codes on the transponder, which the car reads when you use it to start the car.

Common old tech on other marques, quite new to Golfs.

[mcmaddy]

How new is new? It used to do this on mk 4 golfs about 20 years ago.

[fredgroves]

I didn't have it I think on the Mk7?

[mcmaddy]

You will have Fred. Change how the doors open with the fob ie open all or just one and then try with the other key, it'll work differently. Any changes you do with one key won't affect the other key.

[fredgroves]

Ah ok, you just get named driver profiles now which you can alter without having to use the other key...

You can also have more profiles than keys and manually select them (prompted at start up)