How Do I Know If A Remote Key Fob Can Be Used On My Toyota Rav4?

Does the car have power locks and windows?  If so then there is most likely a transceiver mounted in the car somewhere that picks up a wireless signal from a source such as a key fob ect.  Look for the type of key fob offered with some trim packages of the same vehicle as yours and pick one up, go to a site on the Internet that offers free on board programming instructions for programming added key fobs etc to vehicles, you can find these sites by performing a query in basically any search engine regardless of how generic it may be.  Follow the instructions you print out from site.  You have to follow the steps exactly to a tee, and it should work fine. Oh another way to test if it is possible to have a key fob with your vehicle is to take your key place in the drivers door lock and turn it to lock position twice and then hold a few seconds in the lock position, if a key fob is possible the windows should start to roll up on both sides if they were down and both doors should switch to the locked position in unison.