Several remote transmitters used by the major automotive manufacturers on factory-installed and dealer-installed keyless entry systems in the early 1990s have been discontinued. Remotes Unlimited expects more keyfobs to be discontinued because car companies generally review whether or not they should continue to support replacement parts about 20 years after a vehicle model year.
The good news is that Remotes Unlimited offers a ReMoto-brand aftermarket replacement keyfob for many older remotes. For instance, in a recent blog post (see here), we discussed the fact that Nissan and Infiniti have discontinued support for remotes with FCC ID A269ZUA073, which were used on vehicles such as 300ZX, Maxima, J30 and Q45 during the 1990-1997 period. The Nissan and Infiniti OE parts can be replaced by RUI part 106-2666, shown at this link.
Similarly, GM remotes with FCC ID ABO0502T and ABO0702T are no longer available from dealers, but Remotes Unlimited offers ReMoto part 134-2667. See the original and aftermarket replacement remotes at this link.
Even better news is that the ReMoto replacement keyfob is much less expensive than the dealer list price of the former original equipment remotes. And, these remotes are user programmable for most vehicle applications.