Was wondering what is a Flash? Whats does it do for your car? Ive had my car to the dealer 3 or 4 times, will they automatically flash it for me or do I have to ask? Tried searching first, so if this is a repost sorry.

 

A flash is a set of code and parameters that live in the ECU. These parameters determine how the engine and other systems of the car are managed by the ECU. The dealer will automatically update the ECU when they hook the car up to the WDS and it determines that you need a new flash. Mazda periodically releases flashes to fix problems and improve the car.

There is TONS of information on this subject on this forum, so you probably didn't search very hard.

 

To paraphase, the "flash" is the program for the engine control unit (or PCM--powertrain control module). Mazda periodically tweaks it, especially in terms of the fuel/air ratio at different portions of the rpm spectrum, but a new flash could change any of the engine control parameters.