First post, I only joined to share some info about my Comand CD/Nav/Radio in my 2007 W169 A Class which would not turn on beyond the MB logo screen.
I spent several hours looking for a solution to this problem so hopefully the following will save people some search time.
It started when I went through an automatic car wash, during the phase where the most amount of water is cascading over the car the CD I was listening to suddenly stopped playing but the screen still displayed the track info. I changed to a radio station which was fine for about 1 minute and then that cut out too.
I turned the Comand off and then tried to turn it back on but all I got was the MB logo screen which stayed on for about 20 seconds and then a blank screen.
Googling for a solution produced many varied possibilities, some from this forum. I tried pulling the fuses and waiting a while then replacing, that didn't work.
Finally I found a link to a PDF file which describes how to hack into the Engineering Mode in my Comand model, here's the link
All I did was:
Press Comand power on
- MB logo appears
Press Mute - Phone - Serv
in that order
Hey Presto, I now have my Comand working again.
There must be some way for water to leak in somewhere and it probably shorted out the MOST circuit and needed a reboot. No fuses were blown though.
Hope this is useful to some people out there.