simonsay03

Hey guys,

Long time reader & first time poster since 9 times out of 10 a forum search on this site answers most questions.

However: About two weeks ago (after a dead battery replacement) My COMAND unit started flashing the Mercedes Star for a few seconds and shutting down. Forum research revealed that the system either needed to be reset with the STAR or needs a software update or it is is an issue with the MOST network.

So I took it to my independent who thought it only needed to be reset with the STAR. That failed to correct the problem. After he examined the car he thinks that the problem is the main COMAND unit in the front dash; which is going to be a $1,000+ part.

My question is: Before I shell out for the "head unit" (211 870 48 89) could this be software related or another problem entirely? Since I can see the Mercedes logo flash at startup I know the display is fine...and during my thread research I saw that for some people it was as easy as a fuse swap out (I already tried the reset routine pulling fuse #5 in the trunk)....someone had to replace the fiber in the vechile; and someone claimed to be in and out of the stealership in 15 minutes with a software update so my head is going in so many directions...

Can any of you guru's help guide me down the right path?

tashakes

I really doubt that it is the head unit, as it is a pretty simple device with a screen and cd/dvd mechanism, plus, you are getting some response from it (the logo) before shutting down. I had the same problem and replaced the AGW which is in the trunk. There are some out there on eBay, but be careful cause some of them are for European models without Logic 7. I tried one before switching to the correct one. There is a lot of difference in the sound (no sub for one), but if you just want it to work and it is cheap enough, the other one will work. You can always try it and dump it on eBay with a $30-$50 loss if that was not the problem, worth the trouble I would guess.

Good luck.

simonsay03

Thanks tashakes!

My thoughts were right in line with you regarding the head unit...I could not understand why it would display the logo fine for a few seconds if it was broken. I will research the AGW on Ebay tonight and see what I can find. You wouldn't happen to have the part number for the US version with Logic 7 would you?

Thanks again.

tashakes

A2118701589, A2118704289, A2118706989 in order from oldest to newest according to the EPC. All I know is that you have to get the one WITH the built-in fan.

wampa

I also agree, that the COMAND unit is not the problem. Something in your MOST network is malfuntioning. I would check all your connections to see if something came loose, or unplugged. Also take a look at your fuses to see if anyone of them needs to be replaced.

timannnn

+1

I had a fuse go out on my changer and it did the same thing (star emblem showed up and then nothing). Turned out to be a blown fuse for the changer (drivers side dash behind panel, you can find the fuse with the diagram inside the panel).

MB211

Could be any single unit on the MOST loop---CDC/COMAND/AGW/CTEL......

I have a used known good AGW for sale if you need....

SZMB

I had a similar problem in the 2004 E500 2 yrs ago, but it was not caused by replacement of the battery. I also tried pulling fuse #5 out and in and that temporary fixed the problem until the ignition key was removed. The car was under warranty, and the dealer fixed the probelm by replacing the command module -- I'm not sure where it's located and how much it would cost if not under warranty. For odd electricical issues, I would take the car to the dealer for fix since they have the latest diagnostic equipment.

simonsay03

Thanks guys!

I checked all the fuses before taking it to the shop; and then my independent rechecked them.

Based on your suggestions I just ordered this fibre loop so that I can independently test the components on the MOST network and hopefully isolate the problem part(s).

http://www.comandonline.co.uk/most-loop-tool.html

MB211 - I will let you know about the AGW once I get the fibre loop and do some testing next week (shipping from the UK).

simonsay03

Hey guys,

I just wanted to update the resolution to this problem in case someone is searching the threads in the future...

There was obviously an issue with the MOST network. So I bought this tool on the advice from a PM:

http://www.comandonline.co.uk/most-l...ol.html?page=1

Pretty nifty little item. You hook it in place of each item on the MOST network to isolate the problem. Turns out my nav processor was the cause. Once I connected the fibre loop in place of the nav processor the COMAND fired right up. Granted I will have no navigation until I replace the processor...but at least you can leave the fibre loop connected and still have radio/phone/cd changer functionality.

JackZero

Hello,

I've been browsing this site for a while but haven't had any problems with my car until now, hoping you can help me out.

I've got a 2006 E500 4Matic with Nav and 6 CD changer. Recently it developed the problem described above, it turns on, shows the Mercedes logo then turns off. Also the 6 CD changer doesn't open. One strange thing though...the first day it stopped working I was driving to work and it suddenly turned on. It didn't go through the usual logo startup just went from dark screen to instantly showed the map.

The car is currently at the dealership for routine service, plus some other stuff they want to charge me, and they are also looking into the COMAND problem. Yesterday they told me it was showing up as a power/ground short. Today they told me it was definitely the COMAND module and will be $1,300 to fix.

My question is, should I believe them? From what I've read here it sounds like a MOST network problem. I'd like to think they're experts but they're a dealership and it's my first time there, so who knows.

Also, if it is the COMAND (and I can't fix it) is it possible to buy the Euro version and drop it in? I'm was thinking they may need a code, or programming, to work with the car.

Thanks!

Barry45RPM

For a $1300 Sale in these times when all it might need is a minor tweak would mean a $1300 windfall for the Service Dept. Its unethical for them to do it, but times are tough for car dealers right now, and these palaces aint cheap to build, staff & run.

I'd pay for another dealer to evaluate the problem, & if its a true reccomendation that the COMAND needs replacement I'd go back to the 1st dealer to do the work unless the 2nd dealer is much cheaper.

For me, the time & money would be worth the probable savings.

Diesel Benz

They probably got the power/ground fault code from Star. Sounds odd, unless it is from a loose plug at the rear of the Comand.

Did they mean the actual Comand head unit or the Navi processor would be faulty?

You could work a bit on your own too. Reset all MOST components by pulling the fuse off (Comand, AGW, Navi, phone/tele-aid etc.). Check that each unit has the power and the MOST fiber plug properly inserted.

simonsay03

Sounds similar to my issue. I'm not sure if the STAR diag gives a specific code for the power/ground issue - maybe someone else on the forum knows.....but if you'd like to save a few bucks I would suggest buying that MOST fibre loop that I provided a link to in post #9. It was only around $50 shipped and will let you individually test each component on the MOST network. It allowed me to easily identify that my NAV processor was fried because once I replaced it with the fibre loop my system fired right up and the radio came on. I also saved some cash because instead of replacing the $1,300 COMAND I only had to pay $50 for the fibre cable and $500 for the nav processor on *bay. The other thing I liked about this method is that it will give you the use of the other components on your system back (except the broken part) until you repair it. So in my case I got the functionality of the sat radio; cd changer; reg radio back for a few weeks until I found a good deal on the nav processor.....but in your case if the issue is the cd changer at least you will get the use of your nav back for the time being.

You could also pull back the driver's side of the trunk and check for any loose or exposed wires that might be causing the short.....one of the forum members had the same issue but his problem was caused by wires being pinched from the trunk arm....once he taped them up he was ok.

Good luck!

JackZero

Thanks simonsay, I will buy the MOST fibre loop connector. Anyone here want to loan or sell me theirs?

I just brought the COMAND into work, was hoping we'd have a fibre loop here, but none of our fibre had a connector that was even close. I took the unit apart to see if I could use some of the internal fibre as it's own loopback but the parts holding the internal fibre down are soldered on and I didn't want to take it to that level. Didn't take the faceplate off, just the metal housing on the back. I've got some pictures of it opened up if anyone is interested.

Sunday I may be able to tear open the trunk to look for loose connections. Could anyone tell me how to remove the plastic around the tie downs (on the floor of the trunk for securing loads) without breaking them? It isn't obvious where I should try prying them off and I'd like to not break anything.

Thanks!

Diesel Benz

I'm not sure which parts puzzle you. If you remove the screws from the anchors and remove expanding rivets, all panels should should come off easily. Can you clarify or show a photo?

greenmw67

Checkout this youtube video... it saved me $$$...

drexappeal

I know this is an old thread, but I'm so glad to have found it. This might just save me some money, having to replace my Comand!

My issue is similar to the one mentioned on the video on the last post, but it keeps re-booting. Luckily, the place that made the video is also extremely close to my house, so I'll be taking it to them, for diagnosis and hoping that it can somehow be fixed.

Worst case scenario, I end up at square one and have to replace the unit entirely. Just wanted to give this thread a friendly bump, since it was helpful for me.