oil? I have a Mercedes SLK 200. The electronic dashboard oil indicator says Observe Waiting Time, even when the car has been level and stationary for 12 hours. That suggests that either the sensor is malfunctioning, or could it be that there is no oil at all in the system? or too little oil to measure? Is there any other indicator (such as a warning light) that would come on to tell me i'm running with too little oil?
there is no dipstick - you have to rely on the electronic dashboard, which I agree seems ridiculous

I know it may seem a little old-fashioned, but have you tried looking at the dip-stick?

Your engine light would be on if you ran of oil and you vehicle would only run a few minutes before locking up. You didn't say what region you were in but I'm betting it's cold. What it is trying to tell you is that it is not reading your oil heater. Most likely the heater is no longer working and needs to be replaced. If it was your sensor, you wouldn't be getting an alarm at all.