08 S550 4matic radio not working, no sound but NAV works
 

I have a question. My radio stopped working a few days ago. No sound from CD changer, no stations showing on screen, no voice command on steering wheel, or navigation but the navigation maps is working fine.. just no sound. I was told that the CD changer (w221) is bad and needs to be replaced because it's the controller of everything. Wouldn't my Nav not work if this is the case? Also, the changer is lit up and when I push any button on the changer, I can hear it going thru the commands as if it's trying to play, so I'm questioning if this the the problem. I'd like to know before I spend $1500 to replace something that isn't the problem. Thanks

In the 221 the amp (located in the trunk) is the audio gateway (controller) and that's probably the source of the problem, but the failure of any component in the loop can shut down audio as well. Best bet is to get it to a shop with an MB diagnostic terminal and see what fault codes the gateway has thrown.

I took it in for a diagnostic and was told it "could be" the CD changer because it's the brain and not communicating with the amp, but he shows the amp is working. confused.. I'm just afraid to pay $1500 to replace a part that isn't the problem. Thanks for replying

Did they print out or tell you the fault codes? There's a member who's great at this stuff but he'd need the actual codes.

Often a software update will fix these kinds of problems. It isn't very common for electronics with non-moving parts on these or any modern cars to just fail. As Mike mentioned, find out the codes that came up on DAS and Konisteger (sp?) can probably lead you in the right direction regarding needed repairs and service bulletins. He seems to be the most knowledgeable member of this board for this kind of stuff. The S-class is the lowest produced car in the Benz lineup, which means that service techs usually have the least experience when it comes to working on them. So issues like this that are not common might not have been researched enough by the service advisor or tech prior to guessing what might actually be causing the problem.

OK the code what was given to me is:
D104 most ring open at position 1 open.. he says the signal is going out but not coming back

So all of the components...terrestrial radio, satellite radio, voice control, DVD changer, amp...are arranged in a continuous loop, where each piece takes in fiber optic signal and passes it along to the next piece.

If one piece is down, any pieces down line from it go dark as well. The components are arranged on the ring by position. Whatever is at Position 1, and I'm guessing it's the DVD changer, is down.

If you don't mind losing the changer, MB sells a fiber optic bypass for $7.00 that closes the loop, but you'd need to confirm the DVD changer is in the #1 spot and that it can be bypassed. If it's part of the COMAND module it can't.

You Are AWESOME! you repeated verbatim what the guy told me, except the part about the bypass. I will ask on Monday about the bypass option but I believe he told me that the DVD changer was the control module "the brain" is what he called it and it is position 1.

Yeah that's what I'm afraid of. The DVD unit might be the one bit that can't be bypassed. I'd hunt one down on EBay I if that was the case.

I found one on Ebay for $690... they seem to be running around $1,000.. thanks for all of your help.. I feel much better getting an outside opinion becus I didn't want to spend that money and find out it was something else .

That sounds like a safe bet. Let us know how it goes. You ruled out all of the COMAND fuses, right? If not, pull the giant fuse chart from the spare tire well and hunt down any that relate to COMAND. I think you said it still loads but won't play, but I'd check those fuses just to be sure.

I asked him if he checked the fuses, he said yes.. that's what troubles me... I can press , for example, the eject button and you can hear it attempting to eject something.. and all 6 slots are lit up red, so it has power of some sort... that's why I questioned if it was really the changer. My fear is, I'll replace it and discover it's something else. This will get pricey QUICK

Now I'm being told that the amp needs to be replaced as well. I found out today that the amp is NOT the original amp that came with the car and when they replaced it, it was never coded so it's possible that the amp caused the changer to stop working so BOTH need to be replaced. Has anyone ever heard of this happening? :nix:

MY08 part #s. If vehicle is being diagnosed with MB DAS it should identify malfunctioning part. Before replacing anything check to see if amp part # is listed below if so, request they clear fault codes and code amp as a first attempt repair. If CU and/or amp are, in fact, malfunctioning you now have replacement part # to choose from.

I have straight pipe in place of secondary cats in both videos

Similar Problem trying to zero in on cause
 

Hi. I have an 08 s550 4matic with the same symptoms Then043. No sound, CD's won't play, radio won't show stations, and BT phone connects but obviously no sound or mic. I do have maps, and GPS (it just won't speak). I checked the fiber loop as described above and it seems to be closed (okay). So my question is, are there any tests or symptoms I can check myself to zero in on either the radio/cd changer (in the dash) or the amp (in the rear) is the root cause? May not be related but now my backup camera works intermittently.

If you can get it to a dealer or indie with STAR the system will tell you what's wrong. Sounds like a bad amp but the components are so expensive it's worth a hundred bucks to get it scanned.

Thanks for the quick reply Mike!

hi. Did u fix this? Am having this problem so bad

mike help please
 

hello mike my name is Levi i have 07 S550 w221 with most /audio problems is base model so i have only sat radio and tuner(amp) in the trunk. i have xentry/das scan tool with code for most gateway report open loop unknown position d100 i also have a by pass loop tried in all possible modules with no success no sound nav works cd changer loads and reads cds but no radio station numbers are display and obviously no sound, is it possible for the comand to go bad even tho still it appears to be fully functional i could see light on the fiber optics only when i reset the ring with scanner. any help would be much appreciated.

Radio Not working in S550
 

I had a similar problem with my radio everything worked but no sound first turn on the car in on position do a reset hold CD eject button Intel the screen goes blank if that don’t work you need to try a soft reset by taking out all the fuses for 10 minutes In the whole System gps radio CD DVD Gateway amps Voice control module One fuses boxes next the the front door one in Engine compartment The other behind the rear seat I’m not going to go through all the fuses but like I said whole system if that doesn’t work it’s your amp if you live in the USA there is a company called M&B specialist you can find them on eBay or www.mandbspecialist.com I used them and my radio sounds better than it did before loved it and it comes with 6 month warranty for $300 you need to send it out but I’ll tell you highly recommend it

Hello Then043, how are you? please did you ever get this issue resolved? I'm having the same issue. My amp won't even have ignition trigger power..

Hello my name is Alexander I work with this units, what exactly is the problem you have?

Hello you have problem with the amp, most of this amp go bad some transistors but most the commons problem are the PCB controller,is the one that control all the analog and digital signals.

Hello Alexander,

My issue is, someone stole my amplifier in the truck while the vehicle was getting painted.

I bought another on $800 buck.

I hooked up , doesn't work, I tested the voltage, I noticed I only got constant and ground, no ignition. I believe ignition supposed to trigger the amplifier.

I checked all fuses I could find through internet.

Pls do you have the wiring diagram for the amplifier for s550 08. I will appreciate. I only want to know the ignition wire that goes to the amplifier.

Thank you.

Hello azontodance,
I can get it but do you have 12 volt coming in? If you got the voltage this amp should be working if the amp is good. When you power up the radio what can you see? No station? No volume? Blank display? If you unplug the connector from the radio,is the optic cable blinking?

Hello my name is Alexander I do some work in amp and head units. Did you fix the problem?

Check
 

I had the same problem it was the amp but I would take it 2 the dealer just to make sure because it could be a lot of different things The radio runs on a close circuit so if one of the chains doesn’t work nothing works You can get the amp fixed for $300 on eBay but you need to send it to Florida

Hello I can do the repair I being working in this type of units for years. If something I can help let me know.

Thanks
 

Thanks for answering the post but I all ready fix the problem

Ok no problem.

What was the problem with your radio cutting on and off.

I need help
 

I am having the same issue as well. I also thought it was a batt, a ground, or possible thermo overload sw as well. I took it to the dealer as well and they told me the audio gateway is no good. I get the correct amp for the car thru eBay. Remove the old and install the new. The new amp worked for two weeks before it did the same thing which was cut off. Took the new amp out and put in the old amp back in and it worked for almost 3 weeks before it cut back out again. Any advice on what I should do now

I need help
 

Is there anyway we can report this to MBUSA to fix this glitch as a recall because I find it disturbing to be driving a 60+k$ car with no radio and here comes a Datsun with a system louder than mine

Hello Henry,
Before the amp goes out,did that happen when you was listening the music or just when you turn the car on? I know most of the amps in eBay they have problems. If the amp when out when you was listening to music is possible you may have one of the speakers bad if not the amp when bad due the short in the regulator IC when the car turn on. Just let me know. If you what I can check your amp and if can be fix I'll let you know.
Regards.

It happens while I’m listening to it. So now what I do is I take the amp out of the car for a few days and put it back in and it works for a few days then you hear a pop and it goes out for a min and then comes back and then a pop sound and it goes out for a while and come back and then a final pop sound and it’s done

At one point i did think it may be a speaker because I do turn the volume up. But I did try with the volume low and it still cut off

Have you ever update it both units? I know some unit not being updated can cause issue too. But I suggest that check the speakers even when the vol down if you got one defective can affect that too.

yes. When I took it to the dealership for them to look at it, they did do their latest system update on it and it still cuts out

When you said the sound cut off,you mean the amp won't turn on or the sound is cutting in/out? Because if is that the amp turn off and need to wait a couple of hours or days the PCB controller may have problem with the main board and when get hot cause the problem.

Cut out meaning the amp won’t turn on. Do you repair these amps. If so can I get your contact info. Because that makes more sense to me. PCB meaning Power Control Board

Yes

Cut out and back day later
 

Have a 2009 CL550 4Matic: sound drop but nav works. Screen displays "device unavail" for radio/ CD and all other Audio device. There was no pop or loud noise before dropped audio. Day later came back like no prob when started car. Today dropped out and then screen displayed that it was recognizing my phone (BT puck in console) and then failed again. Any input is appreciated. I don't think it is a fuse (#77) as if came back and then out again. Have bought fiber optic loop to test components in trunk (waiting for arrival). Might be amp getting ready to go. Will have to take for diagnostic (clear codes ?)

I think many of you need to see the world differently
it goes wrong because is was very careful designed to do so - it suits the business model they can get away with in the sick world we've all contributed to....

Help
 

so did you even get it to work again & what did you do

S550 radio not working
 

I have a 2013 s550 with similar problem it was the amp check all the fuses first theirs like 7-10 fuses in the fiber optic system Hold the eject button for 10 seconds to reset the head unit try that $300 for amp rebuild it works better than before
https://cimg8.ibsrv.net/gimg/www.mbw...3f935991aa.png

Becker Autosound is you place better.

My car exhibits the same exact symptoms (no audio, devices unavailable, can't see any radio stations, etc.) however it usually starts working again after a few days. It definitely seems to be moisture related, however I've taken the amp apart and there is no sign of moisture damage anywhere. I've inspected the interior compartment that the amp sits in and couldn't find any sign of moisture anywhere. I believe it's moisture related because it fails after there's been rain or snow sitting on the car.

Does anyone have a list or diagram of the MOST ring on a W221 (2011 S550) that would help me troubleshoot other modules on the loop? I have a MOST bypass adapter that I would like to try.

absolutely NO point doing any investigating, swap out the amp with these symptoms its 100% at fault, they die over 6 months some days all good other nothing. The first time it happens just get an amp and get over it once and for all

big or small amp they all die

​​​​​​You should use the loop with the SiriusXM module, just in case you will be able to use cd and USB for audio, something 2011 not just the amp goes bad, the module is one of the main problems in those models.
https://cimg8.ibsrv.net/gimg/www.mbw...cf10fd07cb.jpg
​​​​​​

Alexander,
thanks for the input, the next time it goes out, i will try and bypass the XM module.

Good evening folks.

I have a W221 S550 2008. Before posting, I have read through many many posts looking for a solution to a dead MOST ring. I get an error message of D104 with accompanying comment of "open ring on position 4". I also got a message on my screen that says MOST system will shut down in 3 seconds due to low power. I have checked every fuse in the car. Nothing seems blown. I have not checked the pre-fuse modules (cant find the exact location of Pre-fuse modules). Checked both batteries and I am getting enough power from each when I tested them at the terminals.

The screen is dark with absolutely no functions available except the climate control. The CD player is absolutely dead..

Suggestions anybody? I would certainly be really appreciative for any pointers. Thanks all!

battery
 

Did you check the auxiliary battery. Sometimes if the auxiliary battery is going bad the car will shut down other functions it doesn’t need to keep the car driving

Are there lights on the cd changer? Usually if the MOST ring goes down, the CD changer still has lights and you can load or eject disks. If it’s completely dead, that may be the source of the problem.

ive never gotten the low power warning, that sounds like a good sign... like a fuse has blown or a bad ground somewhere. Not a completely dead module.

buy a MOST bypass loop off amazon and bypass all modules you can reach.

Hi Benzton. I checked the Aux battery at the terminals. They seem to put out 12.4 volts and charges up perfectly.

Hi CStevenson, There were lights on the changer. However those disappeared once I started pulling fuses. There were no blown fuses. Now everything connected via MOST is dead, including the back up camera.
My feeling is that is one of the pre-fuse modules. However I dont know where they are located. I think I should check that before I take it into the garage. I ran a diagnostic on my Autel scanner and I get the message of "D104 : Open Most ring on position 4". On a couple of occasions I have got the message of MOST has shut down due to low/high power. This compliments the message of low power that I got on my car screen.

Hmm, I believe each individual module will monitor its supply voltage and post a fault if too high or low. It’s odd that MOST itself isn’t posting a fault.

it shouldn’t be too hard to track down the component at position 4.

Thanks CStevenson.

Any ideas on which module would pertain to position 4? MOST is posting a low/high voltage error on my scanner. The car itself itself give me the error of low voltage. Unfortunately it does not give me information on which MOST module is posting a open ring, neither does the scanner.

did you end up figuring out the issue I have the same problem !

Unfortunately I have not. However my Audio seems to have come back on line other than the occasional drop in power which turns of the system for a few mins and then comes back on. Like something is resetting or not getting power for a few brief second. I have not had the chance to explore this further. I have given up and the car heads into my mechanic on Friday. Il will post updates when I have it.

I have had the loss in power for a few days and then back to normal. I took it to the Benz dealer and was told I need anew amp for $2400. Then I did research and found Alex Nunez of JP Auto. I too thought it was from moisture, found no moisture, then I thought maybe because of street potholes. When I spoke to Alex we spoke electronic tech to electronic tech(each other) language. So bottom line your amp receives the power and distributes the power to other audio devices. The PCB board in the amp is the issue when it comes down to it. I sent mine to Alex Nunez at JP Auto in upstate NY. He rebuilt it for me and sent it back within the same week. Good quality work, excellent communication, HIGHLY RECOMMEND JP AUTO BY ALEX NUNEZ SHOP#315-543-4555.
If you want this fixed ASAP call this guy

Also, my Benz model is 2010 S550

Might be off topic as to which module is position 4 but i bought online fiber optic bypass (less than $10). Removed side panels in trunk and started with modules. I found that moisture has indeed gotten in.There are funky trim tabs (instead of normal push pin type it is almost rubber like that is an elongated closed tube that the push pin goes in to seal) that secure the rails that run along the side of trunk between the fender and opening of trunk (that are covered by closed trunk deck/lid). The connectors on the satellite and bluetooth had corrosion but the satellite (many models use that same module and cheap on ebay) was bad. You put the fiber optic bypass at each module one at a time. Then turn the car on, if the loop is complete the radio will work just not the bypassed module. Atleast that is what I had to do. My nav worked, just when push radio/sat etc would say device unavailable, cd would load but not play. I thought it was the amp but wanted to test modules first.

Kudos to Alex
 

Hello everyone...After reading this thread a little bit I feel compelled to chime in on behalf of Alex @ JP auto sound. The man is a pro, and gave me an obscenely awesome deal on an amp for my 2008 S600 Carlsson. Price so low my jaw dropped. I met up with him in the Bronx when he came down to visit some family for the weekend and handed him my blown amp, he handed me an expertly repaired exchange.

Last month I started hearing constant popping noises on all speakers. He offered to replace my amp, but first asked that I fiber loop the voice module as it may be bad. BANG, HE NAILED IT. Bought a voice module on Ebay for $50 and no more popping noise and can use voice commands now (no need to program voice module).

With him on this thread guys, there is absolutely no need to refer to M&B audio repair....Alex will not only beat their price, but he is also a man with integrity and takes pride in his work. I can vouch for him....Jeff

Yes. Alex at JP Auto Sound is the man. To all that read this article or thread call this guy for all your MB audio issues. The best in the business I’ve seen thus far, reliable, trust worthy check him here is his info
JP AUTO SOUND
8417 OSWEGO RD SUITE 168
BALDWINSVILLE, NY 13027
Phone: (315)543-4555
website: www.jpautosound.com

MOST Information
 

I assembled some information on the MOST system from WIS and am providing it here, I hope it helps some people.

If your MOST ring goes down, I'd recommend buying a MOST bypass adapter off Amazon and bypassing components one by one until the ring goes back online. This should save you a trip to the dealer, and their diagnosis fee. Hopefully, this method is also more definitive than a "MOST ring open at position #" code. Below is a wiring diagram for USA market vehicles (MY 2011, but it should be the same for other years as well). Amplifier is the MOST controller, and dies frequently as everyone on this thread has pointed out, so I'm not sure what will happen if you bypass it when it's dead. I think the modules communicate independently, so you may still be able to view iPod songs in COMAND (for example) if the amplifier is dead. Bypassing other dead modules should allow the MOST ring to function, it will just list the bypassed module as unavailable.

Amplifier - MOST controller, located in left side of trunk, dies frequently
Satellite Radio - In trunk, optional equipment
Media Interface - Beneath passenger footrest, optional?
CTEL - mobile phone, optional equipment
Voice Control System (VCS) - In trunk
Digital Sound Processor - Optional, for cars with the upgraded stereo
COMAND - The CD changer in the dashboard


https://cimg7.ibsrv.net/gimg/www.mbw...771a213c85.png

front display no power, command center no power?
 

Those units most of the time lost the firmware, probably you may need to reprogram the unit.

[QUOTE=henrydarryl52;8074111]Yes. Alex at JP Auto Sound is the man. To all that read this article or thread call this guy for all your MB audio issues. The best in the business I’ve seen thus far, reliable, trust worthy check him here is his info

anyone know if Alex is a member on here, as I have been trying to call but having no luck reaching anyone. As well does anybody know his prices for a new amp without exchanging the old one?

edit: Alex just called back! Exactly as everyone says, his prices are unbeatable... $500 for a refurbished and repairs at $350, and I believe he stated exchange was $400 or $450! My old amp is stuck out of state at the moment so may have to role with a refurbished amp!

Hi everyone,
Can someone please Help? I have a message on my radio that says device unavailable and the radio doesn't work. It was working fine and all of a sudden it stop. What could be the problem? Is this something that I can unplug and it start working again?

on Yelp , it states his (JP Sound) location has closed/changed. so he must not be in business any longer

I would call the number within my previous post which is Phone: (315)967-4352!

Update JP Auto Sound231 Sherwood CirRock Hill, SC 29730Tel. 803.504.4397
​​​​​​​I believe he moved to SC.

Update JP Auto Sound 231 Sherwood Cir Rock Hill, SC 29730Tel. 803.504.4397
they said he moved to SC.

​​​​​​​

Thanks for the information. Quite helpful. I have same issue of no sound and got it diagnosed and the error that pops up is for the teleaid system malfunction. Do you or anyone have any idea where the teleaid unit is located? From the above diagram i suspect it to be what is named “Voice control system” Mine is a 2007 s550 base.

Radio not working but Nav works
 

I had the same problem call this guys after I sent it to them it worked better then it did before
https://cimg8.ibsrv.net/gimg/www.mbw...3f935991aa.png
I used them and it sounds better then before

Did you get it diagnosed and the computer gave the code for amp? Because i dont see any codes for amp in my car only tele aid , and i dont wanna send to repair amp only to find out thats not the issue

I didn't get an code for an amp fault - I got a MOST circuit see picture - new amp 6 years ago not seen since - nor the lack of sound and tuner channel numbers vanishing
https://cimg7.ibsrv.net/gimg/www.mbw...3bdd811880.jpg

MOST position 3
 

Hi, I have a 2008 s550. Does anyone know what module is at position 3 on the MOST bus?

I had to check each component in trunk along wheel well. I found on the internet a fiber optic loop that let me bypass each unit (satellite, cellular,etc) to figure out which was bad. Atleast on mine each unit was connected in line. If one unit before the next was bad all would show bad. When I figured out which was bad I pulled it and ordered a used one on eBay. That is what worked for me. Pretty fast and simple.

I was playing the other day but didn't write it down

Xentry says you can have any order so long at you tell the car that's what its got (but its wrong !!!) and you need to use the order it wants - which I'm not 100% sure of it right now

guessing I think its this (not all components are on the MOST)

1) comand
2) the amp/tuner
3 TV - if fitted
4) European DAB or Sirius - if either fitted
5) Lingatronic - if fitted - I don't have so can say for sure