Hello,

Recently, my 2004 E320's COMAND system has refused to turn on. When I press the power button, the Mercedes-Benz logo appears and stays on for about five seconds. Then, the system simply turns off. (I never hear any audio.) I tried to reset COMAND using "SERV" mode, but I had no success. I took the car to the dealer, and this is excactly what they said:

"Ran quick test, found faults in audio gateway for component missing on D2B bus. Performed fiber optic tests to all control units. Found no response from Tele Aid. Checked wiring and fiber optic lead. No fiber optics are reaching the Tele Aid control unit. Inspected voice control module. Installed fiber optic test equipment. Verified voice control module defective. It is not sending any light to the Tele Aid control unit. Bypassed Tele Aid control unit with test equipment. Radio began working and sound was OK when both control units are removed from the fiber optic loop. Voice control unit and Tele Aid control unit are defective and do not send or receive fiber optic signal from each other."

The dealer wants $1780 for a new "voice control module and Tele Aid module". I have not renewed my Tele Aid subscription in several years, and I never had Tele Aid upgraded to a "digital" system; however, up until just a few weeks ago, the COMAND system worked perfectly fine. I first noticed COMAND had stopped working when I started the car after I had been parked in the sun (in an airport "economy lot") for a week, if that means anything.

There has to be a less expensive way to get my audio system working. Would I have any luck finding a used "voice control module", or is there a way to bypass it just to have a functional audio system?

Any other suggestions would be appreciated. Thanks for your help!

 

I'm 99.9% sure that you can bypass these defective components in the MOST loop.

 

Teleaid is not a requirement. Matter of fact it can be listed as 'not present' through the DAS.

 

Assuming dealer has correctly diagnosed the problem if not utilizing a phone simply reconfigure the MOST loop eliminating TeleAid and VCM modules then have ring version coded with SDS.

DIY – MOST cables are not clearly marked after disassembling the coupling the most cable connected to the previous component can be determined by turning the key on, the cable that transmits red light is connected to the previous component, the cable without light is connected to the next component. Use this in configuring the ring.

As matter of reference current VCM part #2118206285 (parts.com $397.90)

 

Thanks!

I'm taking the car to an independent shop tomorrow, as I've never disassembled MB audio components and I don't want to break anything. I have another question: do the fiber optic cables need to be spliced, or is there a DIP switch on each component that will effectively let me bypass it? (This shop would rather not cut any cables.) I guess I could put in a new VCM if nothing else works, but again, I have never used TeleAid, and I haven't renewed my subscription since 2004. I just need the radio to work.

 

I know thread old so no need to tell me. 2004 mercedes benz e320 4matic you can loop almost any componet i have looped navigation unit also i used loop in voice communication and on tele aid so it was voixlce controle module got cd and rafio to work again l. Still getting sos malfunction visit workshop is their away to clear thqt without star and mb dealer