I'm hoping the community can save my bacon on what could be a massive invoice at the dealer...

I have a 2011 C300 Sport with the Navi/multimedia upgrade (flip out screen). Here's what happens -

When I start the car in the morning, the music and COMAND all work fine. If I shut the car off after getting to my destination, but restart it again too soon after shutting down the car, the speakers will emit what I can only describe as a pitchy "popping" sound in rapid succession, followed by a steady, softer "pop" that remains unless I turn the system off (using the main power button while the car is running); turning it right back on again or doing a soft reset don't bring the audio back. The screen is lit, the music files will show as playing, NAVI works... it's just that nothing has sound, and the radio can't tune anything (as in, it can't find radio stations, which I'm assuming is because it can't detect prerequisite audio which would indicate a clear radio station). If I leave the car off for 30 minutes or so, everything works fine. Also, it's not EVERY time that this cut out occurs, but it's frequent enough that I need to fix it. When I explained the issue to a service manager at a local MB dealer, he struggled to follow and suggested I'd need a full diagnostic done ($$$) on the system. My experience with the dealer is that their answer to everything is replacement.

To the best of my understanding of electronics, it's almost as though the COMAND is entering a lengthy 'sleep mode' sequence that can't be interrupted or errors arise (kinda like Windows). If it's been just a few minutes from powering off the car (like the length of time it takes to pump gas), the COMAND shutdown/sleep is essentially 'interrupted' thereby glitching the amplifier. When the car is off for more than 15-20 minutes it enters a full shutdown, so it's able to properly boot thereafter.

 

Hi! did you fix it ?I have the same problem no one know what is the problem.

 

I'm still dealing with it. No one has been forthcoming with information and a trip to the dealership amounted to nothing but some 'bro' service manager making me feel like I'm either stupid or crazy.

My best guess at this stage is that it's the main AMP unit, and it's heat related. If the stereo is on for a length of time, and I shut the car off and then back on again, the sound will cut out (no sound, just intermittent 'pops'). Likewise, if it's a particularly hot day the stereo won't play. Just silence with an intermittent popping sound.

 

i had the same issue with h/k sound on my c350 , sorted by buying a new AMP.

 

Did you find the issue with this? Great explanation as this is exactly was I'm experiencing. Maybe an AMP?

 

Spot on. I'm thinking it's amp too, but I haven't bought one yet. I'm currently dealing with my 30-pin connector in the glovebox not working. It's either not receiving power or it's not being read by the firmware... or something else. I'm f**king pissed because it's likely a trip to the dealership to get bent over a barrel for software updates. I'll ask the tech about the amp when I make that appointment and report back.

 

Any updates Ricky?

 

Any updates on this, got the same problem

 

I solved it

I replaced it with a used comand, i bought it on ebay

 

I have the same issue on my 2014 C300. Went to the dealer and they charged me $230 to diagnose; then told me my command unit needed to be replaced (ford $2300 )... No thanks. So after living with no audio for 2 months, it finally came back on this weekend. By this point i had already purchased a used one from Ebay (matching serial numbers to mine). When i plugged it in to the car, it would light up and show controls for a few minutes, then the anti-theft lockout would activate.
When i called Mercedes, they were giving me some BS responses like they wouldn't be willing to program the new (used) Command unit to my car, but i'm convinced it would fix it.

OP- My question, to you. Did you purchase a matching serial number CU and have Mercedes Service Dept program it for you? I also purchased a new to me (used) Amp and will be swapping in at the same time.

Sorry about the long post; wanted to provide background context
Cheers,
Des.

 

When you say "back on", do you mean it back on automatically? By itself? I have same issue with my 2012 C250 Coupe

 

When you say "back on" Do you mean it back on automatically without any reparation? Is it turn back on by itself? I have same issue with my 2012 C250 Coupe.

 

Gents, I also went to the dealership after getting nowhere online with diagnosis. The dealership told me I'd need a new unit for $4,900 - no way, Jose.

As far as buying a used unit, you have to go through a supplier that will "unlock" the unit or give you instructions on doing so. Dealerships will be hesitant to do this kind of work, not only because it's not in their official procedure manuals, but also because it would promote similar behavior in the Benz community. They code these COMAND systems just like you would code an ignition key.

I hope you got your issues solved!

 

I have the exact same problem on a W204 as do hundreds of others. Nobody has cracked this problem and that includes Mercedes Benz. The only available solution is to replace the Command module with another (or dismantle it and replace the amplifier). As a new Command module costs north of US$2k most will go looking for a used unit from a wrecker. Easy on 2007 - 2011 Series 1 cars HOWEVER on Series 2 2011-2014 cars the Command unit is security coded and it gets tricky. If you're trying to replace the Command system with a used unit on this model search 'how to' before attempting the task.Go in blind and you will lock the replacement unit and destroy it!!