No. 4 Changing The Method For Registering Additional 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.

Using any key, turn the ignition switch to the ON position. (Either a valid or an unregistered key can be used.)
NOTE:
- When using an unregistered key, although the security light flashes and DTC 15 is displayed, this does not indicate an improper procedure. Continue to perform the procedure as indicated.
Connect the WDS or equivalent to the DLC-2.
Select "Body/Security/PATS function" from the WDS or equivalent screen menu.
Perform security access as indicated on the WDS or equivalent screen. (See NO.6 SECURITY ACCESS PROCEDURE .)
Select either "Customer Spare Key Programming Enable" or "Customer Spare Key Programming Disable" from the WDS or equivalent screen menu. Depending on the selected menu, the additional key registration method is as shown below:

Fig 1: Identifying Keys For Registration
Courtesy of MAZDA MOTORS CORP.
After verifying that the PATS function menu is displayed again on the WDS or equivalent screen, select "Exit" to complete the WDS or equivalent function.
After Step 6, wait 10 s or more and then turn the ignition switch to the LOCK position.