Shooting in the dark here (as usual) but when pressing the check button in the dashboard (the button next to the odometer/trip reset button) doesn't it introduce this symbol? I see your screen has a bunch of pixels missing so it might be unreadable, but maybe you could make something out.
Usually when pressing the check button, it introduces a bunch of symbols and says what they're about, but I cannot remember whether it introduced all of them or just the more critical ones. Worth a shot I guess.