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

WARNING: This page is about a different car, the 2004 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Have one key (key 3) ready for registration.

Fig 1: Identifying Keys For Registration
Courtesy of MAZDA MOTORS CORP.
Using key 1, turn the ignition switch to the ON position.
Verify that the security light illuminates for approx. 3 s and then goes out.
Using key 1, turn the ignition switch to the LOCK position within approx. 4 s after the security light goes out.
Remove key 1
Repeat Steps 2-5 using key 2.
Repeat Steps 2-5 using key 3.
If additional keys need to be registered, repeat Steps 1--7 in the same manner as key 3.