I found this identical information on both an "authoritative" Mazda site and on 2 mazda enthusiast forums:
Programming a Spare Remote for Mazda3
Step 1: Open driver side door and leave open.
Step 2: Lock and Unlock the drivers door using the power door lock switch on the door
Step 3: Insert key into the ignition.
Step 4: Turn Key to ON position and return to Lock (off) position. Do this 3 times within 10 seconds. LEAVE key in the ignition in Lock (off) position.
Step 5: Close and open drivers door 3 times ending with door in the open position.
Step 6: ECU should respond by locking and unlocking the doors once.
Step 7: Press any button on remote #1 twice. ECU responds by locking and unlocking the car doors.
Step 8: Additional remotes, repeat Step 7 for up to 3 remotes total.
Step 9: Remove the key from the ignition and the ECU will respond a final time with a series (about 4) of door locks and unlocks. You're done!
How do I program a keyless remote for a 2007 Hyundai Azeva
how do you do this
replaced battery and now remote doesnt work . how do you reprogram remote
For now that is a dealer - only issue
The only way to program the key it to take it to a dealer. They change about $100
You can program a Lincoln 2007 remote by first turning the ignition from OFF to RUN, and then unlocking the doors to confirm keyless entry programming mode.
Program key remote 2007 mustang?
how to program remote control 2007 Cadillac escalade
2032
To program a keyless entry remote for a 2007 Buick Lucerne, sit inside the car and close all doors. Insert the key into the ignition and turn it to the "On" position (without starting the engine) and back to "Off" five times within 10 seconds. After the fifth turn, the locks will cycle to indicate the vehicle is in programming mode. Press and hold the lock and unlock buttons on the remote simultaneously for about 15 seconds until you hear a confirmation sound, then test the remote.
That depends on kind of key you have. Smart keys need TIS Toyota software and special cable also activation for key replacement.
Keyless entry remotes must be programmed by a Hyundai dealer.