How do you reset immobilizer on 2003 Mazda 6?

To reset the immobilizer on a 2003 Mazda 6, first, ensure you have the working key for the vehicle. Insert the key into the ignition and turn it to the "On" position without starting the engine. Leave it in the "On" position for about 10 minutes until the security light turns off, then turn the key to the "Off" position and repeat the process two more times. Finally, turn the key to the "Start" position to start the engine. If the issue persists, consult your owner's manual or a professional mechanic.