No. 3 transmitter id code cannot be reprogrammed
Location indexMazda 6 Service Manual: Selector lever disassembly/assembly
1. Disassemble in the order shown in the figure.
2. Assemble in the reverse order of disassembly.
Connector Disassembly Note
1. Insert a thin piece of metal from the terminal side of the connector, and
press down the terminal locking tab.
2. Pull the terminal out of the connector. ...
Mazda 6 Service Manual: Contact Authorized Mazda Dealer and Have Vehicle Inspected
If any of the following warning lights or the indicator light turns on/flashes,
the system may have a malfunction. Contact an Authorized Mazda Dealer to have your
vehicle inspected.
...