You will not find this in the manual, so probably not everyone knows that without any additional devices and without visiting Dealership you can test most of the indicators from the dashboard and change some settings in on-board computer. For example, I use this to change units of the fuel consumption from mpg to litres/100 km. It can be done "in-house", and the key in this case is code "60 d15". I will write about this in another article, first we need to enter to the service mode. For this purpose you need to hold the reset button of daily trip for a few seconds and turn the ignition on. After a while, the display will show: "tE5t" (test), and you can release the button. Now when you press the same button another time you will change an option. When you want to change a setting (and if it is possible), you need to press INFO button from the center console.
I found a table of codes and values on Polish forum www.mazdaspeed.pl, but it's not exactly applied to my version of Mazdaspeed3, so I put my own in another article named Table of codes and values in service mode.