> Ø or ⌀ is sometimes also used as a symbol for average value, particularly in German-speaking countries. ("Average" in German is Durchschnitt, directly translated as cut-through.)
My 2002 VW has the same and it means average over multiple trips. TM probably means this trip? You may have distance of the current trip and average consumption of the current trip (eg 40km, 6.3l/100km), then the last few trips with a combined average for those (eg 1500km, 5.4l/100km).
From wikipedia: https://en.wikipedia.org/wiki/%C3%98
My 2002 VW has the same and it means average over multiple trips. TM probably means this trip? You may have distance of the current trip and average consumption of the current trip (eg 40km, 6.3l/100km), then the last few trips with a combined average for those (eg 1500km, 5.4l/100km).