Hello all - Problems with electronics...Looking for some advice or experience, or dare I hope, solution:

2007 s550 4matic...intermittently the telephone interface, radio, satellite radio and dvd/dc player turns off and COMAND displays "Device Not Available". Note the Navigation, AC/Heater and Vehicle Settings still work fine (except no voice prompts on navi)

If I do nothing, sometimes it comes back on, sometimes not.

If I shut the car down, sometimes it comes back on, sometimes not.

If I pull the main sound system fuse (40 amp / fuse number 104 ) and plug it back in, the system will come back on when I start the car (assume this is a forced reset?)

This has been going on for about a week...will shut off 5 or 6 times a day.

Some additional information that may or may not be relevant or related to the symptoms above:

Just one time, since the "Device not available" issue started, I happened to glance down at the COMAND screen and something to the effect of "Temperature Problem Device Turning Off" appeared and the whole COMAND unit shut down...e.g. Navigation, AC/Heater and Vehicle Settings as well...complete blank screen. Restarted car and all was fine...has not recurred. Definitely not the same as the repeating thing described above.

Also, about 1 month ago, very hot days, I had been sitting at idle (e.g. drive thru line or waiting for kid at school) and the ESP and ABS Systems Not Available error appeared (on speedometer screen, not COMAND as above). Once I parked stopped the engine and restarted this cleared itself both times...I chalked it up to the heat and idling vs driving speed. Not happened since then....I am assuming not related.

Any ideas from the gang out there? I am a geek (read "engineer") so fairly comfortable working with this thing, but not sure where to start.

Dane

 

The intermittent cutting on and off could very well be a Temperature issue. Most electronics have some sort of thermal protection. The ABS and ESP faults will certainly have generated error codes that could be diagnosed. You will likely need to see the dealer or a good indy for resolution. My Volvo had a cooling fan built into the amplifier. It stopped running and my system would cut in and out. Replacing the amp took care of the issue. You seem to have multiple issues going on. Keep us posted as to what your service tech finds.

 

Where are you located? To protect the hard drive from damage, COMAND switches it off at very high temperatures. Wonder how hot it needs to get before COMAND shuts off.

http://www.mersag.com/cmer-2282.html

 

I am in Philly, so not likely that it is that hot. Additionally, it has occurred at night and early morning without any excessive heat.

I ran out of ideas, so its at dealer...will let you know the outcome.

 

One possibility might be the consumer battery located in the trunk may be failing. Has it been replaced? If it is failing, it could cause strange behavior of the various electronic systems.

 

OK...there were two separate issues....the Sirius Satellite radio module was bad, bypassing that unit, and the other functions worked fine....many $ later, new unit and all is well....

The ESP/ABS issue was a speed sensor on front right....un-related....

Thanks to all who tried to help !