I have a 2004 Audi A8L and my MMI stopped working....so I bought the Optic loop tester and checked my CD changer, Navigation and Radio and when I checked my amp found out that the AMP was bad.....once I unplug the optic wire from the Amp everything started to work but no sound.So I ordered a amp from Ebay with the same model number and that did not fix the problem.Could the amp be bad???Any suggestions.



Thanks
Dave

 

You need to do "component protection" procedure to enable the amp to work in your car. That enters the VIN into the amp module among other things to allow it to work. Basically, it's an anti-theft thing. I'm trying to recall exactly what all it does. I haven't been an Audi tech for a year now and some data has gotten lost and overwritten in the ol' brain
Only way I know of to do it is online with a scanner communicating with the Audi database and,,,,,,,you need what's called a GeKo I.D. and that means an Audi tech at the dealer (sorry). This is so Audi knows what module with what serial number is in what car. It also updates the database for future diagnostics, etc......So a tech will see it's not the original the car was built with. Sometimes, this makes a big difference in the diagnostic process.
If everything works with the loop in, it is definitely the amp. They are a common failure. Usually the ONLY thing that fails in the optical loop.
Just to be sure, check that none of the MMI control panel buttons are sticky and that they all light up. The panel isn't on the loop, it only sends signals to the loop modules through the gateway module.

 

If the radio still works does it mean that the amp is ok

 

If you have sound yes...

 

My MMI gives aswell problems, a leak from the sunroof damaged I think my MMI panel. I have cleaned first the hoses left and right from the sunroof down to the wheel area.

My Most ring gives with VCDS no errors so optic must be fine, my MMI panel gives no light or respond, My LCD screen comes up some times and I see the airsystem Lift, Dynamic, Automatic screen, some times other screen. Road trafic messages i hear to.

If the panel is broke has somebody expirience to swap some components on the circuitboard ? I see abnormal prices for used ones on Ebay.

Sheers from Belgium

I drive a USA 2004 A8L 4.2 imported back to Europe.