I bought a used 1996 Chevy Suburban 1500 in Mexico, but it was orginally sold in Califonria. It stays at my house on the Pacific coast.

It came with one ignition key and a remote. I duplicated the key, and it worked fine, and my friends were able to use the dupe to drive the car while I am back in the states. I brought the remote back home with me.

I just heard from them and they are unable to start the vehicle. Whenever they insert the key, an alam goes off. What's the deal?

Anyone know how to fix this?