Adding multiple remote transmitters
WARNING: This page is about a different car, the 2008 Acura TL and 2007 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.
Turn the ignition switch ON (II), push the transmitter's lock or unlock button within 4 seconds and turn the ignition switch OFF, turn it back ON (II) within 4 seconds and back OFF. Repeat this 2 more times and the locks should cycle when the transmitter button is pushed. Push the lock or unlock button on each remote to be programmed within 4 seconds of each other. Turn the ignition switch OFF and remove the key. Wait 10 seconds and verify that all remotes being programmed are functioning properly.