Mercedes spends millions in engineering it's audio system. it’s a complicated mess, one change can screw up the whole system
It's best to leave it stock and find awork around

This is what I did

Sorry I can't help but this is for future readers.

Sent from my iPhone using Tapatalk

 

You could try to code AGW according current options, now if it tries to find devices which are actually not there, it might keep bus awake. As above, why mess with it... Get a Korean car for that

 

I'm pretty sure the Head Unit controls everything on the MOST ring including wake up. If HU is replaced the new unit would need to take over this task.
I'm just guessing here but if you disconnect AGW it will need a wake up signal to come back.

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I did buy a MOST decoder that had canbus wires. The seller just confirmed that the wires are used to signal the gateway. I ended up disconnecting those wires, because when I connected both the radio canbus wires AND the MOST box wires, the radio steering controls didn't work.

When I get some time, I'm going to re-hook the wires and hope that wakes the gateway.

I'm not going through the process of replacing the AGM if it is faulty. If that is needed, I'll just get my own amp and bypass this whole thing.

This is so far than the plug and play I thought it'd be.

 

Which gateway are you using? As far as I can tell, none of them are awesome. The one I'm using only gives me left and right, so I don't get front/rear fade. Annoying. And I still have a quirk. I'm about to give up on it too.

You can give up on the AGW, but you'll have to run wires to all the speakers, which is yet another fun process involving wires in the side conduits and through the doors.

Yes, it's a huge hassle, and I'm glad I had a good shop do mine. I'd have mangled something terribly.

 

I'm under the impression that there are aftermarket amps that do work with the existing speakers. So I could run a bunch of RCAs to the trunk and then splice in wires to the existing speakers. Not even sure if I'll take it that far, I may just put back the old head unit and accept it as a sad turn of events.

This is the decoder I'm using. The seller did say I have it hooked up incorrectly (need constant 12v not switched, and the canbus does apparently control the gateway and needs to be attached) so when I get some time I'll dig in the dash (again) and rewire and hope that fixes the issue

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Solved my issue. The fiber decoder NEEDS to be plugged into the canbus WIRES to wake and sleep the gateway. I did initially, then I disconnected it because having both the head unit and the decoder on the same set of canbus wires caused the head unit canbus not to work.

Plugged the fiber decoder back on canbus, and now sound, and proper shutdown. Hooked the head unit to a different set of canbus, and now that works too.

Bottom line, you NEED a fiber decoder with canbus wires or else you WILL have AGW problems. Probably why that AVIN model doesn't let you return, what a ripoff.

I do get a pop from the speakers when starting the car, but so what. Also my CD changer now opens again. What a waste of time for a stupid mistake.

 

Solved my issue. The fiber decoder NEEDS to be plugged into the canbus WIRES to wake and sleep the gateway. I did initially, then I disconnected it because having both the head unit and the decoder on the same set of canbus wires caused the head unit canbus not to work.

Plugged the fiber decoder back on canbus, and now sound, and proper shutdown. Hooked the head unit to a different set of canbus, and now that works too.

Bottom line, you NEED a fiber decoder with canbus wires or else you WILL have AGW problems. Probably why that AVIN model doesn't let you return, what a ripoff.

I do get a pop from the speakers when starting the car, but so what. Also my CD changer now opens again. What a waste of time for a stupid mistake.

Can you explain what decoder you're using? I'm not aware of an optical adapter that has canbus built in. Are you talking about two separate boxes? One for optical and one for can?

 

Was there a solution to this? I actually do have a MOST adapter with CANBUS wires, but as Lou stated, my radio sometimes just does not power on. When it does, it works great. This is so intermittent I am not sure what causes the radio to not turn on.

 

To follow up here, I think I have this solved. I used my Foxwell MB Tool to remove the CD Changer, NAV, and Tele from the MOST ring. I used two fiber loops and swapped the CD changer fiber connector with the original radio connector, such that the original radio connector has a loop. This appears to have created a situation to which the radio powers on every time.

 

Are you saying that you had an open MOST ring?

 

I am saying that I swapped my loop and head unit converter box fiber endpoints, and then coded out all accessories. Nothing else was changed, no additional loops, no additional physical eliminations.

 

So, you have a loop on the original connector, and the radio plugged into the CD changer input? And that works every time? I'll see if I can do the same.

The MOST adapter I have shows as a CD changer to SDS, and is the only thing on the MOST bus. SDS sees the same.

When I start the car, there are four possible scenarios:

1> Everything works as expected. The dash says "AUDIO" and there is sound from the stereo via MOST to the speakers. This is the goal. SDS shows only a CD Changer on the MOST ring. Doing a MOST reset with SDS will cause a brief hiccup in sound, but leave sound playing.

2> What I believe is the Audio Gateway not waking up, but the MOST adapter comes up and is recognized. The dash says "AUDIO" and there is no sound from the MOST speakers. (The sub has a separate amp, and always works.) Eventually - usually within 15 minutes - the AGW realizes there is an audo signal and wakes up, and sound comes from the speakers. SDS shows only a CD changer on the MOST ring, and doing a MOST test will cause sound right away.

3> What I believe is the Audio Gateway waking up before the MOST adapter powers up, so the MOST adapter is not regognized. The dash says "AUDIO" in smaller letters, higher than usual, and then has "---" below it, indicating there is no audio. No sound from the MOST speakers, and the system apparently never wakes up and starts playing. SDS sees nothing on the MOST ring. Doing a MOST test will cause sound, and for the MOST adapter to show as a CD Changer. The dash changes to "AUDIO".

4> What I think is the Audio Gateway waking up and seeing the MOST adapter, but the car stereo itself not getting the message and not sending audio. In this case, the dash says "AUDIO" as normal, and you can hear the little feep noises the controls on the radio make, and sometimes some features have audio - if you press the "mic" button it will prompt for input, but no music or audio output comes out otherwise. SDS shows a CD changer, and a MOST reset does not affect playback. I think this is a bug in the car stereo itself, because the car and SDS show sensible values and it can make feep noises, it just chooses not to play audio.

Yes, I've sat in the car with SDS and played with this a lot. I drove around for a couple of weeks with SDS in the trunk so I could diagnose it wherever it happened.

Failure mode #4: "AUDIO" but no music, only control sounds, seems to me to be a bug in the radio itself. It's getting confusing canbus messages or combinations of inputs and decides it can't play sound. This is not something I expect the MOST adapter to fix. It also happens very rarely.

I think failure modes #2 and #3 are probably caused by low voltage at start, and by the components powering up and responding to each other in a different order. This is why running short trips tends to cause it more, because the battery may not have fully charged. It almost never happened after a brand-new battery, and has crept back slowly.

I have discovered that if I cause a power drain to completely shut down and restart the car, sometimes #2 or #3 will resolve itself right away. #4 always will resolve with this. Basically, convince the car you've gotten out, and force it to go to sleep. Put it in park, set the brake, shut the engine off. Make sure the lights and any other electric draw is off. Open and close the door, twice. Then pump the brake pedal for ten or fifteen seconds. (This causes SBC to run in my car, and may draw power from the alternate battery, which may allow a higher starting voltage. That's a complete guess.) Let the dash go black - should happen when you pump the brake - and then restart the car. 2/3 of the time, the car will start and you'll get state #1, and everything works.

This is annoying, and I'm not thrilled by it, but it's not a disaster. The car runs, drives, etc. Google Maps just won't talk to me. I can shut bluetooth on my phone off and use the handset.

If I make sure to leave the lights off as much as possible, it happens less.

Anyway, if all it takes is moving the head unit to the CD input and making sure all the others are on a loop connection, that's pretty straightforward and I'll see if I can give that a try!

 

Also, I'm seriously considering just removing the AGW at this point and running wires to the speakers from a standard car amplifier.

My understanding is that the AGW is a switching system and/or mixer so that the many audio sources in the car can be routed to the speakers in a sensible way. This is very thoughtful and a good design, IMO, but makes the amp more complex and very Mercedes-specific.

My understanding is that the AGW handles input from:

• The cellular phone connector or Bluetooth interface
• The COMAND or AUDIO stereo system
• Navigation
• Linguatronic
• TeleAid
• Satellite Radio, or did that come through COMAND?

So, the cell connector and only works with a few phones from the early 2000's, and I don't use it. It would handle the BT puck if I could find one, but that only provides limited interface and I don't use it either. COMAND has been replaced with my new head unit. I don't have the Mercedes navigation system, which isn't updated any more anyway. My car does not have Linguatronic installed. I do not subscribe to TeleAid, and that service will quit working on 31 December 2022 because the cellular network it depends on is shutting down. I do not have a Mercedes satellite radio.

So, for my use, the AGW isn't adding much (if any) value any more.

Most of the things the AGW handled have been replaced (or partly replaced) by my new head unit and smartphone. Phone calls, texts, music, navigation, and satellite radio all come through the head unit. The smartphone does voice recognition but doesn't fully replace Linguatronic, and TeleAid is simply not available. Although, a phone and Internet connection are which means you can get directions and/or call for help. Modern versions of Android will even automatically call for help if they detect a large enough shock, such as an accident.

I'm wondering if it isn't simpler just to code it completely out of the system and remove it, replacing it with a standard car audio amp. The Mercedes interface I have will remain to connect CANBUS and give the steering wheel buttons and such meaning, but the AGW itself, and the entiere subsystem can probably just go away.

I haven't tried coding it out or unplugging it to see what effect that has on the IC or how badly it screams about it. Or if the door chimes, etc., go through it. It may have to linger, powered on with no devices. Haven't looked yet.

Next time I do that kind of work on the car, I may give it an unplugging and see how the car behaves. If I could completely remove it and still have a stereo, that would seem the simplest option. No need to drive that amp with no inputs, and no need to leave a possibly flaky piece of hardware in the system.

So, in the long run, I'll probably replace the AGW with a standard car stero amp, possibly removing the AGW entirely. Possibly leaving it there, like an audio appendix, because getting rid of it isn't worth the hassle. Depends on how much of it I can turn off in SDS.

 

Lou this is right. I did code out components as well. I’m living semi happily with this now.

 

The Analog input->Fiber Optic output "Decoder" does only that. It does not have nor does it need canbus signals.

The canbus lines will go to the new headunit (presumably Android). They are needed to get the steering wheel controls to interface with the new headunit.

Look at the pinout diagrams on the headunit and it will have canbus hi & low connections.

 

Hello

I have an e55 with an aftermarket Pioneer and MOST adaptor installed. I removed the CD changer and NAV unit from the back and on occasion I would get the Audio "--" error and no sound. Not very often and typically restarting the car brought audio back.

I decided to clean up the MOST ring with my new STAR setup- I have long removed the CD Changer and NAV unit in trunk and wanted to remove those in AGW.

In STAR I tried the trick of reading Actual values in AGW then using those settings- my car also showed the MOST Adaptor/Pioneer as a CD Changer. So, AGW Gateway>>>>CD Changer>>>the rest Vacant.

As soon as I did that-, everything went to straight to hell. If the car was sleeping when I started the car I was guaranteed to get the Audio "--" until I restarted, every single time. Also, my driver's seat and door controls on both sides stopped working until the car was started.

The solution that seems to be working is forcing a configuration; instead of letting the car mistakenly think the MOST adaptor is a CD changer, I listed it as a COMAND in position 1. So, AGW master>>>Comand.

Problem seems to have gone way and now audio starts every time I turn the key, power seats have returned as well.

Perhaps the AGW kicks on the amplifiers based on some sort of wake up signal from COMAND, but not a CD Changer. Who knows.

 

AGW has to the the 'master'. It has the amplifier and tuner. The Command unit is usually simply a display and buttons. Your unit now has an amplifier, but you are simply converting the audio output to low level signal to feed back to the AGW in the form of frames streaming on the MOST ring. The AGW then assembles the frames and amplifies the signal again and powers the speakers.

On your MOST config, you should probably simply change CD Changer to 'not present'.

You may notice that the motorized pop-up door for the CD Changer may not open like before. That's a maybe.

 

How can this be a "nightmare"?

 

A most interesting thread to read!

I recently purchased a 2007 E350, and I'd really like to have a back-up camera added to the system. However, as a bit of a purist, I'd prefer to approach a COMMAND replacement fully armed with all the info and all the tools to keep as much of the original functionality as possible, like the steering wheel buttons, the information in the 'heads up' multifunction display (center of the speedometer) like the radio channel and the NAV input like the compass direction and the street / road name.

Has anyone put together a document that explains all the components, their interfaces, and options for replacing or modifying?

If I go with the Android-type unit with the fiber adapter, will the NAV still work and supply the compass direction and street / road name? How about the CD changer below the COMMAND unit?

 

If you remove the COMAND unit you will lose NAV directions and compass on the speedo, but you will retain steering wheels controls, assuming you have it correctly connected to CANBUS. A new HU with real EQ functions will really wake up the sound quality of the stereo.

One other note: You will likely lose radio reception. AM will be totally gone, FM barely working; indicative of a dead power antenna.

The radio install is actually pretty simple, and the backup cam isn't too bad but you will have to drill a pretty large hole in the license plate lamp housing. If you are OK with that you can get a camera that goes where the license plate lamp goes. Pull power for the backup cam from the reverse light harness.

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