No.1 Additional Key Programming Procedure (Using Two Valid Keys): Condition

WARNING: This page is about a different car, the 2008 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

Have two or more valid keys.

NOTE:

A maximum of eight keys can be programmed for one vehicle. If key programming is not successful and DTC 15 appears even though the procedure was performed properly, use the PID/data monitor function of the M-MDS and verify the number of keys that have been programmed.
If eight keys have already been programmed, and it is necessary to program other keys, the previously programmed key ID numbers must first be cleared. To clear the key, refer to "09-14-43 NO.3 PCM REPLACEMENT PROCEDURE ".