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‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
Command unit issues
Hello all,
Been a while since I posted but I recently had an issue with my sound system in my car.I recently had 2 amps repaired by the company who built them so I know it’s not the amps that’s the problem. But recently I noticed that I have no sound or radio stations displayed. What’s weird is that if I unplug the amp then wait a second a plug the black plug in the stations and sound come back. Once I shut the car off and turn it back on the problem reappears. Then I noticed also that the back up camera stopped working and then it would work randomly. Finally today I tried to turn on the command unit and it won’t power up. The command screen is completely black. There are no lights lit up on command unit itself. I checked all the fuses I believe for the command unit. If anyone has any advice that would be great. Is there a relay for the command unit?
I would not say a repaired amp can't be the problem - if you think these are still both OK - no one in the UK that got one repaired has had it last more than 6 months, many don't make it through a month - all the owners gave up and risked an ebay amp - sometimes you need to try two or three before you by one that still works - check returns policy before clicking "buy"
no sound anywhere with no station display on the tuner section of the comand screen and yet everything else about the system seems normal, is the perfect symptom of a dying or 100% a dead amp remember once the amp tries to take down the MOST circuit other things may start to misbehave - my "dead" amp still works but its intermittent - as soon as I replaced it no faults for 4 years
the big clue is the radio station display comes from the AMP in the boot, which is not just an amp but a baldy made amp with integral FM, AM and SW tuners inside.... the station display is sent to the comand unit over the MOST circuit when the amp is having its moment with no audio output, the station naming fails to get out as well
and for those that fancy some fun a genisis / hyundai amp is sort of plug and play for $ lots less - except the volume control is all weird (you can fight each time following a strange back and forth process till you sort of gets you there - but we are still waiting on someone to be brave and flash the genesis / hyundai (almost identical hardware from same OEM) to try and flash merc software at it and see it it goes 100% mercified)
mines first went odd on a hot day during a long run - then over 6 months it would do it more frequently - often it would ok one day, not the next - as I live around the corner from a Merc toy genuine OEM reftofit shop I asked them - everyone in the building said with those symptoms (you too listed) don't even bother to check for fault codes or do any diagnosis - just buy a new amp !!!
I did it sorted it and in the 4 years since, read pages and pages of rubbish by owners than try to do it any other way and years on still in the same place
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
Botus,
as you could be correct that it’s possibly the amps it’s also a bit unlike both amps to be failing. The command screen is black and doesn’t display any picture. I was just made aware that fuse F51 is associated with the screen so tomorrow I will check that. I have the Mercedes star computer and it actually points to a defective command unit. I also read that these units go bad as well. I will report back my findings. I can’t really complain too much as the car just hit 187k miles and even though it doesn’t look like it has that many miles it’s bound to have its issue. The upside is that parts are readily available and I am sure I will get this figured out sooner than later. I recently picked up 2007 Mercedes C280 4matic with 109k miles. Just had the car serviced with all new rotors and pads, brake calipers, brand new ac compressor, transmission service, new tires, wheels powder-coated, android radio and finally backup camera. I bought this car for my son being that it’s v6 it’s decent on gas. Prior to having its serviced it was in really good shape.
I don't think so - borrow a good amp or one that's less bad than yours and see what happens ? note I updated my first response..
well a bit odd - now we get more symptoms... but you can always have lots more than one failure - after all it is a mercedes
the big clue on the fault you posted at the start of this thread - is the radio station display comes from the AMP in the boot, which is not just an amp but a baldy made amp with integral FM, AM and SW tuners inside.... the station display is sent to the comand unit over the MOST circuit, and when the amp is having its moment with no audio output, the station naming fails to get out as well
a black screen can be any module on the MOST circuit killing the network
lots recently said the voice control module likes to fail and take down the MOST - buy a fibre optic link out dongle and give it a go (only $8) - one module at a time - don't link out the amp, as the system can't function without it, and to start with don't bother to electrically link out a module, just the orange fiber link, I don't think the car cares if its got power (when linked out - as their is no data transfer)
As for Xentry saying comand this and that - might be true, but I've had it lie more often than help - if a module is not std, (aka a later better unit) comand makes up lies about various other parts of the system not being compatible, with other modules or indeed lies that the comand software is out of date
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
I have tried my friend’s amp that’s in his w221.. same issue.. I am leaning towards the command unit being bad.. I am pretty knowledgeable on this car. Also spoke to Becker and they said they will check my command unit. I was just posting here to see anyone else had issues like this and what they did..
see the edits I was making between your replies on post 6
wouldn't believe a word of the OEM, they are rubbish units that they were asked to build to fail - but they went mad and made them even more useless than asked
OP does ‘Voice control’ work? I had an intermittent failure in the voice control module cause what you describe almost to the letter. Any component in the loop that plugs into fiber optic cable that fails will take down the full circuit.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
so I tried the fiber optic loop and didn’t really get much success… do you have the part # for the voice control module? So I just noticed that the left steering wheel controls work but the right side steering wheel controls don’t work. These controls are the answering and ending calls as well up/down of audio volume.
QUOTE=JohnLane;8786022]OP does ‘Voice control’ work? I had an intermittent failure in the voice control module cause what you describe almost to the letter. Any component in the loop that plugs into fiber optic cable that fails will take down the full circuit.[/QUOTE]
Voice control module lives in the trunk on the driver’s side (for those of us with LHD cars) just in front of the spare. It is a little bigger then a pack of Pall Mall bare *** smokes. Don’t have a part number for it. I scared one up used on StealBay. Immediately solved an over a year long intermittent issue that had me wanting to fix the car with fire... may have happened but for it making 740lb/ft that gave me something else to focus on.
As mentioned previously any module that goes down will take out the fiber loop.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
It’s to the left of the main battery in the trunk? The trunk panel gets removed and it’s right next to another small antenna module? I will give it a try but when I ran the star diagnostic I got defective command unit, tuner, and something else. I definitely bought a voice control unit back when as I had a similar issue. I will let you know. When you had your issue did the steering wheel controls work?
It’s to the left of the main battery in the trunk? The trunk panel gets removed and it’s right next to another small antenna module? I will give it a try but when I ran the star diagnostic I got defective command unit, tuner, and something else. I definitely bought a voice control unit back when as I had a similar issue. I will let you know. When you had your issue did the steering wheel controls work?
In my 221 S65 it was an intermittent failure that took out the whole loop. Voice control was inoperative even when Audio worked. I would hear a Bzzt and audio was gone for ten minutes to ten days. When audio worked was able to use those buttons in steering wheel... but not voice control as it was dead.
Replacing the VCM solved it. Never cared enough to use voice control even with it working. Stupid gimmick that didn’t work worth a damn in 2008 vintage cars. They have improved a lot over the years though now I holler at Siri to make calls.
Seems like in my car it was further to the left behind the panel that goes fore/aft. Have to remove panel for battery access first. In the photo it sure looks like someone is holding a fiber loop used to bypass a component in the loop.
What’s with 175 photos of the C Class car? Takes forever to load on my old IPad
Last edited by JohnLane; May 28, 2023 at 02:36 PM.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
I recently bought that for my son lol ..
109k completely mine car. Just did a bunch service on it. It’s his first car not bad lol. I had jeep Laredo for my first car.
I recently bought that for my son lol ..
109k completely mine car. Just did a bunch service on it. It’s his first car not bad lol. I had jeep Laredo for my first car.
My first was a ‘72 Impala with a 400ci bent eight that burned as much oil as gas. Lol
two other modules on fleabay with different connections but first one looks like a bluetooth module
2007/2008/2009/2010/2011/2012/2013/W216/ CL600/CL63/CL65/CL550/S600/S63/S65/S550/S450/W221 Interchange Part Number 2218705787 Fitment Type Direct Replacement Brand Mercedes-Benz Manufacturer Part Number A2218705787 Other Part Number A 221 870 57 87
07-14 Mercedes W216 CL63 S550 Voice Language Communication Control Module OEM Part Number #2218703887
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