WARNING
Do not leave the key in your vehicle with children and keep them in a place where your children will not find or play with them:
Leaving children in a vehicle with the key is dangerous. This could result in someone being badly injured or even killed. Children may find these keys to be an interesting toy to play with and could cause the power windows or other controls to operate, or even make the vehicle move.
CAUTION
A code number is stamped on the plate attached to the key set; detach this plate and store it in a safe place (not in the vehicle) for use if you need to make a replacement key (auxiliary key).
Also write down the code number and keep it in a separate safe and convenient place, but not in the vehicle.
If your key (auxiliary key) is lost, consult your Authorized Mazda Dealer and have your code number ready.
NOTE
The driver must carry the key to ensure the system functions properly.

To use the auxiliary key, pull out the auxiliary key from the transmitter while pressing the knob.

Keys
Keyless Entry SystemMazda 6 Owners Manual: Engine Exhaust (Carbon monoxide)
WARNING
Do not drive your vehicle if you smell exhaust gas inside the vehicle:
Engine exhaust gas is dangerous. This gas contains carbon monoxide (CO), which is
colorless, odorless, and poisonous. When inhaled, it can cause loss of consciousness
and death. If you smell exhaust gas inside the ...
Mazda 6 Owners Manual: Rear View Monitor Operation
The operation of the rear view monitor when reversing the vehicle varies depending
on the traffic, road, and vehicle conditions. The amount of steering and the timing
also varies depending on conditions, so confirm the surrounding conditions directly
with your eyes and steer the vehicle in acc ...