Right. So after a week of trouble-free riding the warning light has come on again. This time it is different, though.
This time it is one long, one short, then repeat.
No idea what causes it since the bike is idling / riding just fine. By the way, the light doesn't come on when idling. It comes up when riding only.
This time I won't go to the service shop since I can't find any problem with the riding experience.
Will see what happens next.