No. 3 transmitter id code cannot be reprogrammed
Location indexMazda 6 Service Manual: Rear door speaker inspection
1. Inspect for resistance between the rear door speaker terminals using an
ohmmeter.
If not as specified, replace the rear door speaker.
2. To verify that the rear door speaker outputs sound, apply voltage to the
rear door speaker and release using a 1.5-V battery.
If not outputs ...
Mazda 6 Service Manual: Front buckle removal/installation
1. Perform the following procedure for vehicles with seat belt warning.
(1) Disconnect the negative battery cable.
(2) Remove the front seat.
(3) Disconnect the buckle switch connector.
2. Perform the following procedure for vehicles without seat belt warning.
(1) Remove the console.
...