Mazda CX-9 Grand Touring 2009 Manual page 2053

NOTE:
Within the following procedures, the term a "valid key" means a "key that
can start the engine".
After adding/registering keys, clearing ID numbers or replacing any
component part of the immobilizer system, verify that all keys can start the
engine within 5 s.
When verifying that the keys can start the engine, wait at least 5 s or more
between inserting them.
If the engine cannot be started using a registered key, repeat the
procedure from the beginning.
Fig. 98: Precaution For - Immobilizer System Key
Courtesy of MAZDA MOTORS CORP.
Do not start the engine until the key registration procedure for all the
necessary keys is completed. If the engine is started during the
registration procedure, registration is stopped at that point. Repeat the
procedure starting from the beginning if the engine is started before
completion.
Two or more key ID numbers must be registered for the engine to start.
A maximum of eight key ID numbers can be registered for one vehicle. The
2008 Mazda CX-9 Grand Touring
2008 BODY & ACCESSORIES Security and Locks - Mazda CX-9
resulting in the engine not starting or the key registration failure. Do
not perform the procedure if any of the following items are touching
or near the key head.
Any metallic object
Spare keys or keys for other vehicles equipped with an
immobilizer system
Any electronic device, or any credit or other cards with
magnetic strips