ltooz_a6_a8_q7

You might have bought the part that's not necessary. Disconnect all added MOST bus components and you may fix your problems.

Cheers,

<a href="http://www.dognmonkey.com/audi/an-open-circuit-test-on-mmi-2g-most-bus-and-vcds-read-out-results.html">Louis</a>

Pawel S

Hello,

ltooz_a6_a8_q7 thanks a lot for this video! I am going to follow your troubleshooting right away and report back. Nothing worse than "throwing parts at a problem" and hope it will fix it, I agree with you. I followed TSB from Audi from all data DIY which said when liquid is spilled on MMI controller, replace controller, that is the only reason why I did that.
One little detail that is different from your symptom, my MMI never wakes up with Audi MMI logo screen, it's black all the time even if I reset MMI pad. I am adding couple of more pictures to show how this 3rd party rear camera device is wired (picture after I bypassed this 3rd party device and went direct to control head) There is a wire with some plastic housings - would there be a fuse inside to check?

storka

Have you checked everywhere they have spliced into the original wiring ?

ltooz_a6_a8_q7

Right now, you have NO MMI, which is optical loop. Only find components that have optical connectors. Your back up camera and add-on may not have the optical connector except the Audio one.
Check all the LEDs on every MOST components to see if they're blinking and where they stop, it does take about 30-60 seconds for the loop to run before it stops. You have enough time to check. Every time you hit a key on the panel, the loop start running until it stops because something broken in the loop.
Don't remove anything and create more unknown causes.
Now, the MMI screen doesn't display, it's the connector from Head unit. But even if the display is not there, all LEDs should be on.

Every thing was working fine before you spilled the drink? Just to make it clear.

BTW, CAN bus components can die and the system still works because it's connected parallel UNLIKE MOST optical bus, daisy chain.

Cheers,

Louis

Pawel S

One thing at a time - correct. I reconnected the 3rd party rear camera lvds module as it was when whole MMI system was working.

The MMI system was 100% functional for last 18 months since I owned this A8, it went dead the moment I spilled coffee on controller pad.

Ok here are the Fiberoptic test results. Ignition switched on for approx 10 sec- looking for red light, then off:

Y - means fiberoptic red light is present
N - red light not there

CONTROL HEAD

Fiberoptic cable connector Y
Control head module N

TELEMATICS UNIT

Fiberoptic cable connector N
Telematics module Y

CD CHANGER

Fiberoptic cable connector Y (small blink twice or three times see video link)
Cd Changer Y (led light seems weak see video link)


NAVIGATION

Fiberoptic cable connector Y
Navigation module N

SATELITE RADIO

Fiberoptic cable connector OK
Satelite radio module N

AMPLIFIER

Fiberoptic cable connector Y
Amplifier module N

storka

Did you ever buy a optic test loop ?

Pawel S

I am not sure what that is, would you mind to post a link to it? I will buy it if needed

storka

Most Fiber Optical Optic Loop Female Connector Adapter FOR VW Audi BMW Benz | eBay
Can bypass defective module

Pawel S

Thanks!
Based on the fact I am not seeing LEDs from the following modules:
control head
navigation
satellite radio
amplifier

I should get 4 of these optical loops...

Does anyone know if the dealer sells these optical loops?
Does anyone have a diagram how the fiberoptic is connected through the car?

Thanks

ltooz_a6_a8_q7

Plug the main head unit and look at other to see if the blinking still exist, one by one and the bad one will stop the blinking, imo