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How To Reprogram Keys And Fobs On A Mazda 3

Discussion in 'Auto Modifications Section' started by admin, May 19, 2014.

  1. admin

    admin Administrator
    Staff Member

    Jan 23, 2008
    Likes Received:
    As you may know, the Mazda3 has a built in security system that utilizes a key with an embedded transponder chip that is read by the car's ECU when you start the car. The ECU is programmed to accept only certain transponder codes. If a key's transponder is not registered with the ECU it will not allow the car to be started.

    This is a system that Ford has developed and has so far proven very effective at reducing auto theft, while there is nothing that will prevent a determined, prepared car thief from stealing a car system like this make it nearly impossible to start a car by hotwiring or breaking the ignition.

    Mazda Operations seems to think that their customers are complete idiots and are incapable of wiping their own nose. They don't include instructions in the owners manual for programming additional keys yourself, instead they instruct you to go to your dealer to have new keys made and programmed.

    Reprogram Keys

    To allow a spare key to start the car, you need to start out with two working keys for the Mazda. This is security precaution to make sure someone with one key can?t activate another one, for example, a valet who has the key. If you only have one key, you?re out of luck and will have to take the car to Mazda to have it done. In fact, many people recommend buying a spare key and doing this procedure so that you always have three working keys around (you only receive two when you buy the car). That way if you lose one, you still have the ability to do this procedure on your own.

    Here is how you do it:

    1. Insert the first working key into the key slot and turn the ignition to ON. Wait about 5 seconds, then remove the key.
    2. Insert the second working key into the key slot and turn the ignition to ON. Wait about 5 seconds, then remove the key.
    3. Insert your new/spare key into the key slot and turn the ignition to ON. Wait about 5 seconds, then turn to OFF. This should add that key?s information to the on board computer and allow it to start the car.

    How To Reprogram the FOBs

    This procedure is a bit more involved, and it reminds me a bit of the Konami Code from Nintendo. You?ll need access to all the FOB units that you want to enable for the vehicle. Apparently you can only have three active FOBs at the same time, so don?t try and program more than that.

    1. Open the driver side door
    2. Lock and then unlock the door using the button on the door. Leave the door open.
    3. Insert a key into the ignition and turn the car to the ON position. Leave for about 2 or 3 seconds, then turn off. Repeat this two more times (3 in total). Leave the key in the slot in the OFF position.
    4. Close the driver?s door. Then open it. Then close it. Then open it. Then close it. Then open it.
    5. The onboard computer will respond by locking and unlocking all the doors at this point. That means it?s ready to accept FOB programming
    6. Press a button on each FOB unit to program it to the computer.
    7. When you are done programming FOBs, you can simply remove the key, which causes the computer to cycle the door locks once more.

    I did both of these procedures in under five minutes, and now have four working keys and three working FOBs. So if you are in the same scenario and are feeling a little adventurous, you can simply reprogram the keys or the FOB yourself and save both time and money.

  3. MangaAddict

    MangaAddict New Member

    May 28, 2014
    Likes Received:
    Thanks for the advice, I have a friend with a Mazda 3, I'll send him this link.
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