Mazda 3 keys

[sideshow]

I had to change ecu in a mazda 3 so I changed dash cluster aswell from matching car

then I had one key that suited the orig car
and I borrowed another key fm another running mazda 3

i programmed both keys all went ok

but the key I borrowed from the running mazda 3 , when I went back to it , it would not start ,
Its like one u program a key to a car it won't work on another car
i then had to use the two keys I had to program them back to the running car to get it going

so now I need to find a spare mazda key to finish this job

I thought the chips could not be modified because they don't have a battery in them
or is this normal for mazda keys

Thanks

[arvedo]

that ecu takes EDC16C3 psa?

[keygargoil]

yes thats right when u programme the key page 4 changes to the car its being programmed on so even though the key is registered to the car it wont pass the challenge and response from the ecu and you cannot add it back in because it already registered the only way is by clearing all keys out and registering 2 keys so you need another key

[sideshow]

ok thanks for the info

hopefully shop will find me a spare key for it by monday

[Brilliancezw]

It may need caution i did the same procedures as well on a mazda 3 atenzza 2005 and all keys got lost fro e cu memory. the programming went well and all keys as in the 2 keys none of them was properly programmed to the car. i took it to a friend and says it needs a file to the ecu can i have the file if you have