Friend's BA remote is locking my AU... FRUSTRATING

[IboughtanAU]

Hi guys, I'm quite new here.

Only other Ford I own is my father's XW GT, and this AU is the newest of the Fords I've played with so far. Have had experience owning 2005 BMW M5, 2000 Mazda RX-7, Valiant Charger, etc. But no new Falcons until this AU came along...

Anyways, I have a 1999 AU1 Falcon sedan, base Forte model, in very good condition. I've been slowly fixing it up as an every day car, and its quite good for what it is.

It runs the older Smartlock style of "security" system.

A friend of mine has a BA Falcon, XT base model sedan. One of the very first BA's, an ex-taxi that is really shagged and has done in excess of 695,000kms.

Anyways, he can be a bit of a tool. His favorite prank involves parking next to my AU and then locking his BA with his remote. This makes my AU lock the doors as well, often with my keys in it........

Now, I bought the AU off him, in order to save what is a very good, well looked after vehicle.

I am wondering if he has got inside my AU and programmed his BA key to my AU, really slyly, so he also has "control" of my car? Would this have been possible? Because I thought that BA keyfobs and AU1 were not compatible at all.....?

He keeps locking my AU1 and unlocking it with his bloody BA remote, and he thinks this is hilarious as hell.

I've had enough of this. Is there a way to get my AU to "unlearn" his goddamned BA remote and then only learn my AU remote?

In any case, I honestly thought that AU1 and BA remote and security systems were not compatible at all, so how the bloody hell is this even possible? What has he done?

Sincerely, very unamused AU owner.... :/