2005 E320 W211. Today, for the first time, the car refused to do anything when I attempted to start it. Lots of key twiddling followed, for possibly five minutes. Then, as suddenly as it had stopped responding, it decided to react and the engine started. My journey was short, possibly less than a mile, but I noticed that the engine symbol was illuminated in yellow the whole way. Anyway, we arrived and the engine was turned off. Ten minutes later ........ same performance. Nothing at all when the key was turned to the start position and again, when it finally decided to start, the same yellow engine symbol was illuminated. This process happened several times. When running the engine seemed to have plenty of power, it ran smoothly as far as I could tell and the water temperature remained normal. After this had happened five or six times, everything cleared up ....... it starts immediately and the yellow engine light isn't lit any more !! Any ideas anyone ? Should I trust it ?