This was posted in another forum. If you want to unluck your trip computer here is the procedure, but this only works on 06/07 mazda 3 and mazdaspeed 3's It wont work on earlier models because the radio is different.
Put key in ignition but don't start the car.
Hold down the AM/FM button and cd button at the same time
while holding the buttons start the car, Your radio will say hello and then it will change to say DIS on,
Once it says DIS on release the buttons and turn off the car.
Start the car again and press the set button to scroll through your trip computer features. If you want to reset your average milage or average speed, you need to hold the set button down while they are selected.
Press the clock button to get your clock back.
Now let party
(breakn) (nana) (idhitit) (dance)
Put key in ignition but don't start the car.
Hold down the AM/FM button and cd button at the same time
while holding the buttons start the car, Your radio will say hello and then it will change to say DIS on,
Once it says DIS on release the buttons and turn off the car.
Start the car again and press the set button to scroll through your trip computer features. If you want to reset your average milage or average speed, you need to hold the set button down while they are selected.
Press the clock button to get your clock back.
Now let party
(breakn) (nana) (idhitit) (dance)