Yesterday, I parked the 450 for a couple of hours and then returned to it. Car was dead. By that I mean it would not start, there was no display on either the main screen or the instrument screen, and no welcome notes or graphic when I entered. Car was unlocked so I do not know if the door locks would have worked.

After a short time of sitting in the car, a little spiral started to circle on the main screen. A few minutes later, the car would start and parts of the display screens came back. For example, the rings around the speedo and tach were there, but no needles. I drove away and, over the next five minutes everything came back - piece by piece. By the time I reached the MB service dept. the car was behaving normally. I asked service if I should worry. The response was "This is a really weird glitch. Worry if it happens again". The service rep then proposed a possible cause. The car has two batteries. The secondary battery is charged by the alternator and will also take charge from the main battery. It the secondary battery is drained (why?), it can cause the sorts of symptoms I observed. After a while, that battery takes enough charge from the alternator and/or main battery to function and the car reboots system after system until everything is back.

Sounds reasonable. I am not sure if the service guy really had any idea beyond the weird glitch thing, but the explanation could be valid. I will follow instructions and avoid worry until (if) it happens again.

 

Did they load test your 12 volt battery, the smaller one? All electronics runoff the 12 volt, so if it dies or has low voltage, I predict it will cause the things you observed. Question is why did it die? Is it not holding a charge? Bottom line, your 12 Volt battery may be going bad.

 

Or, you could be experiencing what several of us have, and that is a faulty module that needs to be replaced, not just reflashed.