Do I need a radio code and ....
 

(1)

I understand that my audio system (on my 2007 pre-owned MX-5) may or may not have a security code input by the previous owner. How can I check whether it does or does not. I am unable to contact the previous owner - or do I just wait for a major headache when I first disconnect the battery please ?

Ask a first posting newbie:), may I also ask:
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(2)

What workshop manual should I buy - Do Haynes publish a manual for the 2007 model or Bentley's ?

(3)

Is there / where is the socket for a DTC or more a sophisticated diagnostic testing and where is socket please ? Do you folks use Mazda-specific diagnostic software on a laptop and, if so, who sells it ?

Thank you

I've been thinking...

Supposing I assume that no security code was ever input to the audio system, then I try to input one as recommended in the user manual. Either the audio will (1) accept the code I input, (2) it will show an error message or (3) it will lock up.

If the result is (2) or (3) above, I can try the code reset process suggested by Blue in this forum and hope it works ?

Er how risky is that ?