W212 Comand unit not working
Thread Starter
Junior Member
Joined: Apr 2022
Posts: 20
Likes: 7
E class w212
W212 Comand unit not working
It all started with turning off and on then it stopped turning on at all , after 2 days it turns on and all good then after 2 weeks same problem , I recently changed the battery and everything else works expect the comand unit there’s no signal to the screen as showed in the video i checked fuse number 26 it was fine i guess that is the fuse for the command , any idea what could be the problem?
Senior Member
Joined: Sep 2019
Posts: 266
Likes: 305
2011 Mercedes E350 4Matic Wagon
It all started with turning off and on then it stopped turning on at all , after 2 days it turns on and all good then after 2 weeks same problem , I recently changed the battery and everything else works expect the comand unit there’s no signal to the screen as showed in the video i checked fuse number 26 it was fine i guess that is the fuse for the command , any idea what could be the problem?
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
HEAD COMAND
As indicated by @Raj1471 you need to scan the whole chassis with a compatible scanner such as Launch cReader...
At the end of the day your issue has the following possible causes:
There's a fair amount of No2 defects caused by an unknown internal issue of either capacitor or solderless connection.
These units are built like "Fort Knox". Repairability may be limited.
Personally awaiting for the day I will be forced to fix my own unit. I think it's hard to get in because its easy to fix... duno yet!
At the end of the day your issue has the following possible causes:
- faulty module on the "MOST" ring
- defective CMD head <<
- (bad footwell GND post)
There's a fair amount of No2 defects caused by an unknown internal issue of either capacitor or solderless connection.
These units are built like "Fort Knox". Repairability may be limited.
Personally awaiting for the day I will be forced to fix my own unit. I think it's hard to get in because its easy to fix... duno yet!
Last edited by CaliBenzDriver; Mar 22, 2024 at 02:33 PM.
Thread Starter
Junior Member
Joined: Apr 2022
Posts: 20
Likes: 7
E class w212
As indicated by @Raj1471 you need to scan the whole chassis with a compatible scanner such as Launch cReader...
At the end of the day your issue has the following possible causes:
There's a fair amount of No2 defects caused by an unknown internal issue of either capacitor or solderless connection.
These units are built like "Fort Knox". Repairability may be limited.
Personally awaiting for the day I will be forced to fix my own unit. I think it's hard to get in because its easy to fix... duno yet!
At the end of the day your issue has the following possible causes:
- faulty module on the "MOST" ring
- defective CMD head <<
- (bad footwell GND post)
There's a fair amount of No2 defects caused by an unknown internal issue of either capacitor or solderless connection.
These units are built like "Fort Knox". Repairability may be limited.
Personally awaiting for the day I will be forced to fix my own unit. I think it's hard to get in because its easy to fix... duno yet!
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
I don’t have the scanner to scan it. I took it to a local garage where I usually go. The scanner didn’t want to work for some reason, so I gave up on that. Later in the evening, I detached the comand from the car to check if the problem was from the fuse behind it, but it wasn’t. Tomorrow morning, I will take the comand to a shop famous for fixing comand units like this, so hopefully, they can fix it. I will update when the job is finished.
Whatever you decide do NOT perform a "factory reset" function... it requires dealer programming to fix that.
Member
Joined: Oct 2015
Posts: 136
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2015 S600, 2014 E550 4-Matic
Our 2014 E550 is having a similar issue. I'm able to connect to both the head unit and display, even though neither is functioning (no audio or image on screen). I see all of the OEM headunits are listed as backordered, and a remanufactured unit is available at our local dealer for $3500. I'm not sure if anyone has experience with these faults, but the intermittent nature seems like a hardware fault/solder connection.
Last edited by Turboaction; Jul 29, 2025 at 09:10 PM. Reason: Added diagnostic info and photo
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Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
these Xentry screens make it seem more of a DISPLAY fault than COMAND itself, right?
Now you can fund what's involved with a diagram.
Both Display + Comand modules are normally soldered to stay reliable.
Has Comand been moved around lately to cause a bad connection?
Now you can fund what's involved with a diagram.
Both Display + Comand modules are normally soldered to stay reliable.
Has Comand been moved around lately to cause a bad connection?
Last edited by CaliBenzDriver; Jul 29, 2025 at 10:06 PM.
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Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
these Xentry screens make it seem more of a DISPLAY fault than COMAND itself, right?
Now you can fund what's involved with a diagram.
Both Display + Comand modules are normally soldered to stay reliable.
Has Comand been moved around lately to cause a bad connection?
Now you can fund what's involved with a diagram.
Both Display + Comand modules are normally soldered to stay reliable.
Has Comand been moved around lately to cause a bad connection?
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
It's a strange issue for sure. It started happening two days ago. There hasn't been anything otherwise unusual with the car. Both batteries are about 2 years old, and the alternator is charging normally (max voltage of ~14.4V).
Maybe this is the time to try installing one of the Android displays?
Maybe this is the time to try installing one of the Android displays?
There are online shops than can fix up your own NTG with whatever reset, hardware or update it needs to work well.
Last edited by CaliBenzDriver; Jul 30, 2025 at 01:47 AM.
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
One of the times when the display turned on, the screen had purple or strange colored vertical lines on the screen. This tells me there's a hardware failure with the display, as it's hard for me to believe the head unit is failing in a way that the digital signal is causing vertical lines in the LCD. I asked the seller of one of the Android IPS systems if it will work if the factory display is not present and/or failed. Either way, I'll also see what resources are available online to repair the head unit. I might even be able to do the repairs, but I'm not sure if it's worth my time (I've repaired car stereo amplifiers, power supplies, headlight modules, V12 coil packs, etc in the past).
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
One of the times when the display turned on, the screen had purple or strange colored vertical lines on the screen. This tells me there's a hardware failure with the display, as it's hard for me to believe the head unit is failing in a way that the digital signal is causing vertical lines in the LCD. I asked the seller of one of the Android IPS systems if it will work if the factory display is not present and/or failed. Either way, I'll also see what resources are available online to repair the head unit. I might even be able to do the repairs, but I'm not sure if it's worth my time (I've repaired car stereo amplifiers, power supplies, headlight modules, V12 coil packs, etc in the past).
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
I see you also found concerns with the solder-less connections. I've already soldered the pins in the multi-contour seat pump of my W222. Knowing this questionable construction is widespread, I will certainly check the front SAM, COMAND screen, and COMAND head unit for opportunities of improvement. I think my problem may be with the front SAM, as messing with the fuses seems to have more comprehensively broken the radio, yet no fuses blown. Power at the fuse, but may not be getting delivered to its destination!
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
UNSTABLE NETWORK MODULES
I see you also found concerns with the solder-less connections. I've already soldered the pins in the multi-contour seat pump of my W222. Knowing this questionable construction is widespread, I will certainly check the front SAM, COMAND screen, and COMAND head unit for opportunities of improvement. I think my problem may be with the front SAM, as messing with the fuses seems to have more comprehensively broken the radio, yet no fuses blown. Power at the fuse, but may not be getting delivered to its destination!
Having disconnected fuses guarantees additional upset issues.
> Do a chassis reboot + clear faults to get back to a working condition.
F-SAM + Display + COMAND are not solderless modules but many CAN-B and CGW are made unstable.... Rebooting does work wonders including to restore favorable ECU conditions.
Last edited by CaliBenzDriver; Jul 31, 2025 at 01:34 PM.
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
Oh boy, has it been a day. I spent some time on Xentry and can't get the head unit to turn on (flashing ON button). Only the display has a fault (953D Signal Low voltage differential has an open circuit), aside from the mbrace module having a fault for the audio cable for muting having a short circuit to ground. I'm not even sure where the audio can be muted on the car besides the steering wheel and head unit. Is there another location that has mute wiring? I plan to check wiring diagrams next to try to see where the display wires are actually routed.
I tried starting the COMAND with the display removed, but the display in the dash doesn't show the nav/audio system as active. I'm not sure what's required to get the COMAND system to start. Next I'll check the fuses in the rear fuse box/SAM, but I wouldn't think any of those would affect the audio. The COMAND is reporting good voltage, and all of the connections are securely attached. I also said HI to the mechanical hard drive attached to the bottom of the COMAND unit.
I tried starting the COMAND with the display removed, but the display in the dash doesn't show the nav/audio system as active. I'm not sure what's required to get the COMAND system to start. Next I'll check the fuses in the rear fuse box/SAM, but I wouldn't think any of those would affect the audio. The COMAND is reporting good voltage, and all of the connections are securely attached. I also said HI to the mechanical hard drive attached to the bottom of the COMAND unit.
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
Ok, I have a path forward:
1. Remove the XM radio module and install a bypass loop on the MOST network
2. Disconnect battery and clean ground post on the driver's side footwell
3. Install Android screen upgrade (including new cable for display)
4. Purchase local used COMAND unit and code using Vediamo (my laptop is too slow to run the VMware image so I'll have to setup my desktop in the garage) or request service from Benzninja
1. Remove the XM radio module and install a bypass loop on the MOST network
2. Disconnect battery and clean ground post on the driver's side footwell
3. Install Android screen upgrade (including new cable for display)
4. Purchase local used COMAND unit and code using Vediamo (my laptop is too slow to run the VMware image so I'll have to setup my desktop in the garage) or request service from Benzninja
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
Today I looped the XM module with a fiber loop, and installed an aftermarket Android display. The COMAND still will not boot, so I don't believe it's the XM module, or the screen. I was quoted $1,100 to repair my COMAND unit, so I think step 1 is to try to take apart this COMAND and look for an obvious solder defect. If none found, I'll order one of the many COMAND units available and see if Benzninja or another member can provide an unlock code. This will provide motivation for me to learn how to use Vediamo and either unlock the radio and ILS headlights, or brick one of the modules!
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
I was able to successfully replace the head unit with one I purchased on ebay. It was simple enough to transfer the face of the old head unit to the "new" one. Xentry reported the MOST devices were in the wrong order, so I had to code them in the correct order for the car with Vediamo. This was also used to unlock the head unit thanks to Trigital.
I disassembled the old head unit to remove the old CD's that were in the changer. All of the circuit boards are entirely surface mounted components, so there was no way I was going to be able to repair these boards with my skill level. I thought I'd post the result, as this endeavor cost about $250, vs over $3500 had I gone to the dealer.
I disassembled the old head unit to remove the old CD's that were in the changer. All of the circuit boards are entirely surface mounted components, so there was no way I was going to be able to repair these boards with my skill level. I thought I'd post the result, as this endeavor cost about $250, vs over $3500 had I gone to the dealer.
Newbie
Joined: Feb 2011
Posts: 2
Likes: 0
1999 E320
No sound
The sound stopped working.. I downloaded using Xenty. D018 and D017 Ring break and ring break position 1. I can see the red light in and out of the interface module over the glove box. I'm not getting a red light at the amplifier or satellite in the trunk . There seems to be a communication module somewhere in between N123/4 says B15D814 fault . I can't find the module in the left side of the trunk 222-901 40 02 is the part number. I've read it is a weak spot in the Most loop. Does anyone not where it is for a 2014 E250
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
According to AI, the module could be in a few different places. I don't doubt this, as my replacement head unit had the components in the MOST network in a different order than my car (even though it was also a 2014). It sounds like you should just remove all the trunk paneling and look for that module, and also check the satellite/XM/Sirius antenna module as well (if they aren't the same module).
Location in the 2014 E250:
• It's typically mounted behind the rear seat backrest or under the rear parcel shelf, depending on the exact trim and configuration.
• In some cases, it may be tucked behind the trunk liner on the left or right side, near the fuse box or amplifier.
Location in the 2014 E250:
• It's typically mounted behind the rear seat backrest or under the rear parcel shelf, depending on the exact trim and configuration.
• In some cases, it may be tucked behind the trunk liner on the left or right side, near the fuse box or amplifier.
Newbie
Joined: Feb 2011
Posts: 2
Likes: 0
1999 E320
I have pulled the left rear side out as I was checking the fiber signal to the satellite box and the amplifier. My last car had a bad amp when I had the same issue but not simple this time...I've seen it reported under the front and rear seat, by the fuse box on the right rear. Mine has the DEF tank in the spare tire area so it's a little different. Looking at the rear shelf next. I can follow the harness from the amp to the back seat then it disappears...more digging Thank you,
Member
Joined: Jul 2006
Posts: 193
Likes: 7
From: Alameda, CA
1991 SC Miata, 1999 W210 Estate Wagon, 2014 W212 Sport Wagon
Ugh. Mine just started acting up today (I've just had the car three weeks... lol!)
The Screen state would vary:
a) sometimes it would stay in that "check your surroundings" warning message
b) sometimes it would be stuck with the 360 camera permanently displayed
c) sometimes it would have "please wait" message
I've done all these things (not in order):
1) turned button on/off
2) removed fuse #26 (verified that the info screen died) and re-installed (verified that the screen turned on)
3) removed engine battery (measured 12.4V)
4) replaced engine battery with one from my W210 (measured 12.6V)
5) did the "hang-up" button+1+# combo to enter diagnostics mode... did not work.
I don't have Xentry (looking into getting one... but not sure how often I'll use it).
AI says a firmware update might work. Also not sure what that entails. Almost feel like taking this to an indy hoping that it'll be a cheap and easy fix. Worst case is I send it to Bavlogic. Are there other options?
BTW, does the Comand unit control Lane Assist, Self Park, etc? Because this car has all those features and I'd like to keep them.
The Screen state would vary:
a) sometimes it would stay in that "check your surroundings" warning message
b) sometimes it would be stuck with the 360 camera permanently displayed
c) sometimes it would have "please wait" message
I've done all these things (not in order):
1) turned button on/off
2) removed fuse #26 (verified that the info screen died) and re-installed (verified that the screen turned on)
3) removed engine battery (measured 12.4V)
4) replaced engine battery with one from my W210 (measured 12.6V)
5) did the "hang-up" button+1+# combo to enter diagnostics mode... did not work.
I don't have Xentry (looking into getting one... but not sure how often I'll use it).
AI says a firmware update might work. Also not sure what that entails. Almost feel like taking this to an indy hoping that it'll be a cheap and easy fix. Worst case is I send it to Bavlogic. Are there other options?
BTW, does the Comand unit control Lane Assist, Self Park, etc? Because this car has all those features and I'd like to keep them.
Last edited by ron m.; Oct 11, 2025 at 01:13 AM.
