Mazda radios - Mchenry
This comes from a French source and may not apply to British market cars, but it might save someone some hassle and money.
The standard radio fitted to some new Mazdas is supplied free of a security code and the owner can code it if he wishes. If the radio is left uncoded and the battery is disconnected (which will happen sooner or later in any vehicle's life) the radio becomes locked up with an UNKNOWN security code. Mazda France have confirmed this and the only known solution is to ...fit a new radio!!!