"Telephone not installed" on MMI display
 

Hi there again. So i get the "Telephone not installed" message on my MMI display when I press the "TEL" button. In VCDS I get "no response from the controller" and during auto-scan it says it cannot be reached. I did a Optical Bus Diagnostic test in VCDS and it shows "ERROR" on both electrical and optical.

So I thought it was a bad module(below the driver's carpet) so I switched it out with a known working one but still the same problem. There's 12V coming through the connector but shouldn't there be a red light coming out from the MOST connector when the ignition is on? Could it be a break in the MOST loop? But shouldn't I get a response from the module in VCDS if there's power to it? The fuse is OK.

Also, if there's a break in the MOST-loop, shouldn't all modules in that loop stop working then? I've one more that shows "ERROR" and that's "1E - Media Player 2". Don't know which one that is

Anyone got some insight? I'm assuming that the "Voice Control" is connected to the Telephone module because that is not working either

D3 4.2 2003

And I promise I'll introduce myself. I'm waiting to take a full picture of the car. Right now it's in the garage, which it has been since I bought it :ROFL: Not funny though

Voice control is a module that piggy backs onto the analogue radio in the boot in the media rack. You can look at photos of it on ebay and see if you can see it in the media rack. It looks like a big silver heatsink.

I don't know about the telephone, I wonder if it is coded incorrectly or the incorrect telephone type has been coded/listed in the CAN Gateway?

If the MOST bus is broken, it does stop everything on the bus working and they usually make clicking sounds like a relay. It even breaks it if you power down a module. If you unplug the connector it breaks the bus too.

It sounds as though your module is powered up but not working on CANbus or something like that.

Yeah, it must be powered up because it has not broken the MOST bus.

Is there something I can check in the "CAN Gateway" module in VCDS?

I'll also check if I've the Voice Control module in the rack

EDIT: Well, there was no Voice Control module in the radio unit in the boot. It says that the car came with that option. Hmm. So can I just install one and then it should work?

Hi 'classexa'; if you have a 2003 car, you'll have the original 'SIM in the Arm' phone unit known as the "Telefon EU".

I had exactly same issue with my 2005 A8; "Telephone not installed" message but the MOST Bus must have been 'up' as the rest of the MMI worked.

Swapped in a pre-owned one off eBay and it all worked again.

Suspect the condition you and I had was an internal error in the phone hardware that didn't affect propogation of the optical signal round the loop.

Are you sure the replacement is/was a working unit?

Julian