Hallo zusammen,
danke für Euer Feedback - letztendlich möchte ich aber doch wissen, ob das System defekt ist oder ich mich nur zu blöd anstelle 
Ich habe es heute morgen zum 4. mal probiert, der Crossi stand natürlich auf einer ebenen Fläche und war auch gut 10 Min. aus, bevor ich es ausprobiert habe.
Irgendwie verstehe ich den Mechanismus auch nicht zu 100%. Schlüssel auf "On", dann sollte ja schon das Ölkannen-Symbol im Tripzähler kommen. Das funktioniert bei mir schon mal nicht, es erscheint gleich der Tripzähler. Wie ist das denn bei Euch? Das im Manual beschrieben zweimalige Drücken des linken Knopfes bringt nur die Service-Anzeige zum erscheinen.
EDIT:
O.k., ich konnte noch eine zweite Anleitung googeln, diese weicht zwar vom Text im Handbuch ab, aber ich werde es heute Abend mal testen.
Checking Electronic Oil Level
Make sure the car has been shut off and on a level surface for at least 5 minutes.
Turn key to ON/RUN position.
Wait about 10 seconds
You will now see an oil icon along with a clock icon. Press and hold the knob / button 2x and it will now display the oil level properties.
It will display the following : OK, -1.0Q, -1.5Q, -2.0Q, H
O.K. = Oil level is ok, enjoy the rest of your day!
(-1.0 | -1.5 | -2.0) = Oil level is low, add the suggested amount of oil, run the car, shut it off, and check again when time allows.
H = Oil level is too high. Have some oil drained out of pan until it reaches the proper oil level limit. If you have just done an oil change, it is best to run the car for several minutes before checking electronically or manually. The oil filter will absorb some of the oil which could effect the readings. If a clock is only displayed, it means you haven't let the car sit in the off position long enough. Wait a few minutes and try again. You can also check the oil level from the dipstick located in the engine bay.
EDIT 2:
... und noch eine abweichende Version:
CHECKING ENGINE OIL LEVEL
A sensor in the oil pan allows oil level to be checked without opening the hood. It provides an accurate measurement of oil level, whereas the low engine oil level indicator warns that oil level is definitely too low.
With the vehicle parked on a level surface, the engine is warmed up and shut off for approximately five minutes.
When the ignition switch is turned to the ON/RUN position, press the knob to the left of the speedometer once and wait seven seconds. An ISO oil level icon appears in the trip odometer window and a “clock” icon in the cumulative odometer display. Pressing the knob to the left of the speedometer twice within one second displays one of the following messages:
² OK
² -1.0 Q (-1.0L)
² -1.5 Q (-1.5L)
² -2.0 Q (-2.0L)
² HI
The indicated amount of oil must be added to the engine. If the message -2.0 Q (-2.0L) blinks and a signal sounds. The HI message indicates that the excess oil must be removed from the pan to avoid possible engine or catalytic converter damage.
If the ISO oil level icon and “clock” icon remain on when attempting to check oil level and no message follows, or if the low engine oil level warning lamp comes on, a malfunction in the engine oil level system is indicated. A conveniently located dipstick allows manual checking of the oil level.
If no leaks are noted, continue to drive to the nearest service station where the engine oil should be topped to the “full” mark on the dipstick with an approved oil.
Gruß
JJ