No audio
 

Trying to trouble shoot my radio theres no audio but the screen is fine

Just to clarify. Is it a volume issue? As in it will tune stations etc but there is no volume?

Disconnecting my rear battery for a while renewed my radio when it did the same thing as yours.

I can tune to different station but cant play cds or hear any thing. Tried disconnecting battery that didnt work. I get one red flash on optic loop to cd player but i fell like theres no power to player. Checked fuses 57,66,77 they all looked good

Just saw a 2009 CLK320 with same issue, turned out to be a bad amplifier. Open your trunk and if you smell something burning or an unusual smell that may be your first clue, however, not all amplifiers that go bad have a burning smell.

If you smell something burning in the trunk of an R230, I'd worry that it's a bad battery control module that about to catch fire and cause lots of damage.