compconsult

I have a 2007 SL550 with around 55,000 miles and had to replace the starter battery around 1 year ago, then a few months ago started having problems with vario roof not operating until driving the car for 15 minutes or so and eventually I was getting the RED errors of Brake function because of low battery voltage. So I replaced the rear battery. Ever since replacing the rear battery when I turn on the ignition my radio comes on to FM at 87.9 Mhz with volume up loud to hissing because of no reception at that frequency. I reset all of my sound settings and preset stations and satellite stations and all is good until I shut the engine off. Then the same thing happens every time I start the car. I have checked all fuses in all 4 locations and cannot find what is causing this. I'm hoping that another member has seen this issue.

moretech

I'm not an expert by any means on this one but try turning off the radio (that is, if you always leave it on) and turning it on after car is running and see if it the same. Also do your interior lights come on when opening the door in the morning? Start car and manually turn on dome lite. When my rear batt went bad I had interior light problems on start up till replaced. If your radio works fine after starting car (but is off when you start it) it sounds like some connection is poor or low voltage on start up. Perhaps another member may respond to further troubleshooting wiring headaches. Another point is I am not sure if the radio is always "hot" regardless on engine on or off so my test above may show "no change".

moretech

moretech

compconsult

moretech thanks for your response. I do turn off the radio before shutting off the engine but the radio comes on by itself after starting the engine to a blank station and all settings are lost. The interior lights are working as they should and the clock does not lose its setting. It acts like there is a memory power connection not connected so that is why I removed and checked all fuses. I was able to download a Command schematic but it was not much help.

moretech

I guess I can't help you here. I feel this is a COMMAND problem but let us see other comments on this. When off it should be OFF is my only thought.

moretech

Rudeney

There is only one power supply lead for the radio and it's hot all the time (from fuse 77, rear panel). The function that turns the radio on and off with the ignition is not like with older cars where there was a +12V "accessory" lead. Instead, your car's radio turns itself on and off based on commands it receives over the CAN bus. If it were losing its power supply with the ignition off, then it would not have power with the ignition on, either, as fuse 77 is on circuit 30, which is always powered. My guess is that the COMAND unit itself has developed an internal defect.

moretech

Thanks Rodney for your help on this one.!!
Compconsult : If you pull it to be repaired let us know how that works out and it's cost. Feedback on final solutions to problems really helps our membership keep our cars going well.

moretech

Ronnies550

compconsult

Thanks for the info guys. I'm not happy to hear it may be a Command unit issue that will need repair though. It sure seems odd that I had no problems at all until replacing the rear battery. And I removed and re-installed the battery cables in the correct order per shop manual. Is there a relay or controller for the Command unit? Ronnies550 how did you reset the command unit on your car?

Rudeney

I think you can press and hold the power button and it will do a reset. I know it can also be done through SDS.

compconsult

I will try that. Where would a person go to get the Command unit repaired besides the dealership?

Rudeney

Well, you won't go to a dealership unless you want them to install a whole new COMAND for $2K. I've seen some guys in the forums mention that they had their COMAND units sent off for repair, but I don't know where. There might even be eBay sellers who advertise there for repairs.

compconsult

I tried the reset through the system controls, and when that did not fix anything I did the reset by removing all fuses related to the audio system. Again no help. Next I guess I will pull the unit and take a look at it for signs of a short. In my older 1996 Mercedes you needed a code when re-installing the unit but not sure if they are still doing that?

moretech

For my '03 model no code is used. I think it is married to the car. I find no mention of a code in the manual either. It was one of the 1st things I asked about when I bought the car.

moretech

Rudeney

No code needed.

ItalianJoe1

Best bet on these older cars now, is a replacement android based head unit from an Ebay source. We have a 230 in the shop that needs a radio and it's like $6k and isn't available anyway. You can get a more modern unit that is largely plug and play for around $600 online and it will have all the functions of a modern smart phone, without losing too much OEM functionality.

Ronnies550

There is a system button around display. Go through it until you find reset command. Reset it. Everything went back to normal for me. Find it and reset. It worked for me and put my radio back in sync with NAV and speaker. Don't be scared. Restart the car and ...you will be happy...cause I was.

compconsult

Well I tried all the different ways to reset the system and nothing changed so I am pulling the unit out to take to a repair shop. I called a Mercedes radio repair and told him my issue and he said he thought there was a memory power issue and it does not sound like a Command problem. I told him I had thought the same thing but was told on this forum that there is only 1 power source and if the radio works then it is getting power. So in the process of removing the unit now. Will update this thread when I find out something.

compconsult

I have spent many hours trying to remove the Command unit. After watching Youtube videos on removing the unit I found for 2006 R230's after removing the cup holders you only need to release the plastic lip at the bottom of the unit then it drops down and can be removed. But on my 2007 it is still held very tight so I found a video fpr a 2009 R230 that says there are 2 bolts holding the unit at the top and you need to remove the clock / speaker cover to access the bolts that hold the A/C vents in, after removing the vents you are supposed to be able to access the top bolts holding the Command unit. I have done all that and the unit is still held in by something that I am not able to find so far. This is becoming very time consuming. Will keep you updated on progress.

moretech

the blank! blank! model year variances can drive you nuts!! I'll agree to that. Keep us posted and best of luck.

Moretech

ItalianJoe1

Those vertical bolts often hold sliders that pull up and lock the radio in. Usually you need to loosen the bolt somewhat, then push it down to unlatch it from the radio. If the bolt is removed fully then the slide pushed down, it will fall into the center console and can be a pain to remove.

Rudeney

Here are all the WIS docs:

http://benzbits.com/R230/RemoveCente...nelMY2005-.pdf
http://benzbits.com/R230/RemoveCupHolderMY2005-.pdf
http://benzbits.com/R230/RemoveCenterSpeakerPanel.pdf
http://benzbits.com/R230/RemoveCenterAirVent.pdf
http://benzbits.com/R230/RemoveCOMANDMY2005-.pdf

According to WIS, since yours is a MY2007 (i.e. pre-MY2008/code 809), all you need to do is unclip it
from the bottom, behind the cupholders. However, did you find top bolts behind the center vents? If so, it may be mounted like a MY2008. BUt if so, and you removed those bolts, it should be free. Maybe it's just a bit "stuck" and needs some prying at the edges of the dash to release it from the MB-Tex surface.

compconsult

The only bolts I found on top of the unit were actually small screws that I believe are part of the metal case and did not actually hold the unit in. I do see one bolt on each side at the top of the plastic housing that look like they may swivel the plastic housing so I will try to loosen them to see if that helps. Thanks to all of you for your help on this.

Rudeney

The top "bolts" under the vents are actually just Torx head self-tapping screws. And they are almost impossible to see without a mirror.

compconsult

I was finally able to remove the Command unit last Thursday. There were no bolts at the top holding it in, it was just stuck and after working with it for some time it just popped out. I took it apart looking for a burned circuit but did not see anything that looked bad so I re-assembled it and shipped it to Short Circuit Repair in San Jose. They just called me to let me know that they did find a problem and they want $1,085.00 for the repair. They said on a free estimate they do not go into any details of what is wrong until I commit to the repair. I asked them to give me a couple of days to decide. I'm hoping I can find a decent after market unit to take its place that will have all the functions of the current unit. I will update on what I do soon.

compconsult

After searching the aftermarket options and not finding anything that I felt that I would be able to have all the functions of the factory system working I decided to go with the repair. They said they will give me the cause of the issue on the invoice. They said 6 to 8 days for the parts to arrive. I will update when I know more.