Remote key not locking / unlocking

I received two keys when I bought the car. One that looked well used and will lock / unlock the car perfectly well. The second looks unused but did not work. I have replaced the battery but still dead.

I am happy that I can still manually lock and unlock the car but it would be nice to have both keys working. Is there something that needs to be done to pair the key to the car?

It’s the standard key, not the keyless one.

If you go the Mazda dealer route it will not be a cheap solution, if the second remote is faulty the cost of replacement from Mazda without the key as well is in the order of £100+ . The second remote then needs to be paired with the car which I believe in this case involves removing all paired codes and then using new codes supplied by Mazda coding the two remotes , this costs around £45. Hopefully a dealer will advise you whether it’s worth risking the fee to pair that second remote.

However I believe there are other non Mazda ways which I’m sure someone will advise.

Registering Keyless Entry Transmitters NB & NC

  1. Shut all doors and remove key from the ignition switch
  2. Open drivers side door
  3. Insert key into ignition, switch ignition on, then off then remove key 3 times.
  4. Close then open drivers door 3 times (all doors should lock then unlock)
  5. Press unlock button twice on the transmitter (doors lock then unlock to confirm)
  6. Press unlock button twice on all other transmitters to be registered to the car (doors should lock and unlock to conform each transmitter registered)
  7. Switch ignition on to cancel set-up mode.

Done it myself and it works. 

Crikey, that’s quite a list. When you say Close then open drivers door do you mean lock then unlock or physically close then open?

I assume 1 to 5 is done with the working key?




Yes, you start with the door open, then when you get to the door part just shut it and open it 3 times, don’t touch the locks.
It only takes a few minute to complete the whole procedure.
As long as the key turns the ignition on and off that’s the key to use, you can then programme the other.
I’m assuming that both keys work but not the keyless entry. That is what you are programming.

Do this first as it usually works:

Go very close to the car and press both buttons on the remote control and
hold them pressed until the flashing red light goes off.
Then press the big button once and then again.

That should reset it.

If the OP has factory transmitters then that is not the procedure for them. The accessory Cobra alarm transmitters are the ones that work with that procedure.


Thanks for all the ideas and help guys. Resolved the issue.

In the end I am very embarrassed to say very easily. It was a brain error in the end. I’d installed the battery the wrong way around 


What a muppet. Anyway I’ve learn’t a lot by asking the question which might help someone else