I can use the steering wheel control for increasing or decreasing the volume on my COMAND, but I cannot control the volume with the volume knob on the unit itself. The knob is not damaged and all other functions of the unit work just fine (telphone, navigation, radio, CD, etc..).

Anybody out there ever had the same issue?

 

Try pulling the fuse for the comand to "hard-reboot" it, this will likely rule out software issues. If it still doesnt work after that, you are likely looking at a hardware issue, meaning you are in trouble...

 

Also go here and try a system reset...

http://www.mercupgrades.com/Mercedes...rticle-13.html

Hope this helps.