How do i reset the Mazda 3 central locking?

The procedure for resetting the central locking on the Mazda3 is as follows: Press down on the LOCK button Your remote key FOB and hold it down for one second, then, within 5 seconds of putting the key into the ignition and turning it to the ON position, without starting the engine, turn it to the off position, and then hold the lock side of the driver's door lock switch for 20 seconds. You can also try resetting the ECU, which is as simple as disconnecting the negative lead of the battery, and then turning on the headlights, and subsequently pushing the brake pedal up and down 5 times. (This is to clear residual electricity). After 15 minutes, the ECU should be reset, as will the central locking, and You can reconnect the battery.