So on my way to work I am using the route guidance with the Nav system and I have the lady telling me turn here, turn there, and I remembered that while she is speaking if I hit the "mute" button on the steering wheel it will mute her commands but still keep the nav directions running. Well when I did this I lost volume control of my Comand both on the steering wheel and the knob on the dash. I cycled the comand system several times to no avail. I couldn't shut the car down as I was on the highway. When I got to work I did a complete shut down of the car, let it sit for 15 mins and started it back up. Problem solved and now the volume works. Anyone ever have this or something similar happen to them? I am not sure exactly what button combo I pressed but I will try to replicate it on my way home.

Anyone?

ok, dumb question, but did you hit mute again to unmute? LOL

Maybe I did. I found the only way to get her to speak directions again was the hit the RPRT button on the Nav screen. So does a combo mute/mute button press lock the volume?

ya, she doesn't answer until you almost reaching the turn/exit..!

well, he did say he lost control using both the volume buttons and the control knob (which would automatically override any previously muted audio).

OP, I am thinking you may have "fat fingered it" and hit mute + volume up or volume down accidentally, which confused the electronics. That has happened to me a few times before. Simple restart solves it. Gotta love the over-engineered electronics and mechanics of a Mercedes-Benz.

Pushing RPT should give the next voice command, regardless of where you are in your route.

I must have "fat fingered" it as others have posted. On my trip home I could not replicate the problem I encountered with the volume being stuck.

It happened again today. But now the volume control only changes the route guidance volume level. The radio is still stuck at one level. I am gonna look at the comand manual and see why this is happening and how to "switch it" back to control the radio.

I you pressed steering buttons UP and DOWN, and tried to turn the physical volume knob---and there is still no change in volume, then you may need a software update...I remember back when this happened in my W203.

Once again, gotta love the over-engineered electronics and mechanics of a Mercedes-Benz.

This is really driving me crazy. I get to work and power cycle the car and it's fixed. So I try to do it again. Here are the exact steps I took:

Radio is playing. Volume works fine
I go to Navi and select a destination and start route guidance.
As the lady is speaking it can turn her voice volume up and down while the radio stays the same. I can also mute her.
When I return to the radio the volume will not work.

However, after I power cycled my car this morning I did a quick drive to Duklin Donuts and did the exact steps above and everything worked fine.

So I am stumped. Go By to call MB USA and see if they heard of this.

Hahaha, good luck! Calling MBUSA about a Mercedes Benz is equivalent to calling Kia about a Mercedes Benz! They don't know $h!t, and are just going to tell you "let me look into it" or "please take it to your nearest Mercedes Benz dealership", to which they will say "customer states volume will not work on radio; could not duplicate gripe; everything is working fine"

This happened all the time, and I guess the gremlin has somehow made it way up the W212. I get your frustration, just be glad it doesn't make a high-pitched screeching sound, as soon as you turn the radio on, that you cannot get rid of. It did that to me too, and drove me crazy!