Bjonne

Hi

It seems I have an opening on the MOST ring somewhere in my E60 from 2009.

The car is prewired for CDC but when I connect the CDC (to the fiberoptics in the glove compartment) it doesnt work. If I instead connect the CDC directly to the radio (bypassing the fiberoptics in the car it works perfect)

Can anyone tell me where the normal places is to attach stuff to the MOST ring ?
and maybe how to check if its open in these locations.

Thanks in advance
Bjonne

Gee_115

How do you connect it directly to the radio? You have an LCI, so yours might be different from mine. If you had an open most ring then your radio, bluetooth, amp, etc., would not work at all. Do you know if the car was already coded for the CDC?

Bjonne

Hi Gee

The car has a M-ASK Champ 6.5 inch screen/radio. Behind the radio the firber optics is connected. By connecting the CDC directly to the radio using another set of fiber optics cable everything Works : controlled using the iDrive controller and the steeringwheel buttons.

The car doesnt have nav/bluetooth etc.

The car had the CDC prewire option, and I have had it coded for the CDC now. And the CDC Works perfect connected directly to the radio.

Gee_115

It sounds like the MOST to your CDC is not connected to the rest of the system. Did it come with a covering which would serve to complete the circle? If it did come with the covering then what happens if you do not insert it, does your radio still works?

Bjonne

Hi Gee

The fiberoptics in the glovebox has light in it, so its connected.
The radio plays fine with or without the MOST since amplifier etc. is build into the M-ASK CHAMP unit (I guess)

I think the fiberoptics/MOST goes something like :

RADIO -> Glovebox -> Place X -> Place Y -> RADIO

and I think that "Place X" or "Place Y" etc. isnt correctly connected, meaning the signal/light wont return to the radio and complete the MOST ring.

So when I take a seperate fiber cable and plug it in the RADIO I get :

RADIO -> CDC -> RADIO and so the ring is complet.

Gee_115

That is what I was thinking. the problem with that theory however, is that if you don't have anything else that works on the bus then your ring is already complete. If you don't have an amplifier, etc then there is no place x or y. unless it is pre-wired but it would have a cover to keep the ring going.

I am looking through the TIS to see if I find anything. I saw a diagram with a MOST hub on the left side of trunk under the covers. I don't recall seeing that in my car so I am not sure.

Gee_115

I found some literature on the MOST BUS. The sequence in your car should be MASK>CDC>MOST Terminal>MASK. Try that area I mentioned, behind the trunk cover to see if you can find the terminal. Check to make sure everything is securely fastened. If the terminal is not there then I have no idea where it is.

ncsugrad2006

order doesn't really matter in and of itself. It's just a big loop

The important part is that everything is connected with all the "ins" to "outs" and vice verssa

dbond

The last seven of your VIN would help to understand what you have in the MOST loop. You might have AMP, TCU, SAT Radio, HD Radio, TV Tuner, Head-Up display. The likely culprit as everybody mentioned is the broken loop. Identifying all present MOST modules will help with the troubleshooting. For now we know MASK to CDC connection is OK.

Bjonne

The VIN is C091358

dbond : The car has nothing except the radio (In Denmark the extra gear cost alot so nothing is mounted as standard, only the radio (not even nav))

Gee you write : "That is what I was thinking. the problem with that theory however, is that if you don't have anything else that works on the bus then your ring is already complete. "

But if the car at some point had other stuff installed but was taken out before I got the car, then there might be an open loop, I guess