What does the code u0155 mean on 2008 mazda3?

SOURCE: 2008 mazda3

Start by removing the colored strip which is over the radio display.
(best way is to open the glove box and get underneither it, the right end kind of hooks in at an angle while the left end locks in straight. so work your way to the left first and then the right)

once that is removed, you shuold see four (4) standard screws, remove and save them.
You must remove the top air vent piece, just tip up and pull forward gently.
You will have to disconnect the hazard switch plug also

the stereo set can now be removed by pulling forward gently.
Only two cables are connected to the unit, one can be pulled out, the other must be unclipped.

At this point the WHOLE UNIT including DISPLAY should come out of the console.

On mine, there were directions on how to install and uninstall the CD/MP3 player and if you flip it over you can see where the MINIDisc would go (if you don't have one)

That's it!