C6 and D3 both have their phone modules under the passenger floor....


.... both can be got to with a little effort with the passenger still firmly in place.

My bet is still that its missing or been looped out.

If the unit goes faulty, it dies and breaks the MOST bus, so the whole MMI goes off.

For it to break enough to report as not installed, but not enough to break the fibre loop seems like a long shot to me...

There is no coding to enable a module either, if its on the most bus. It boots and becomes part of the system. Its really pretty fool proof......

I wouldn’t if you can avoid, my car went mental when the battery went flat. It threw up about 30 odd fault codes. They all cleared but scared the schnitzel out of me!

Mine did :ROFL:

I know.... thats why I went for 'long shot' rather than impossible..... +++

Thanks all. Carpet is easy enough to take up so I'll do that to start with and see whats what under there at the weekend.

Still haven't fully got my head around RSAP, whether I have it, need it or want it but I understand it might solve the connectivity / signal issues.

Just as an aside, the same issue affects the VW Passat (maybe other VWs as well). My brother couldn't get his phone to connect despite BT being installed and active. The proposed solution found on one of the VW forums was exactly the same... disconnect it, cycle the ignition, reconnect, and try again. Unfortunately, his still won't connect.

Have you been tinkering in the green menu? Seems odd that the fitted and working module now is not assuming its dry etc.

Have you tried another possibly older phone to see if it works?

It says telephone is not installed (i.e the module) rather than telephone is not connected, i.e. when the module is online but there is no phone connected to it....

I can also confirm that my A8 phone unit went bad but left the MOST Bus working. Only noticed when the phone icon wasn't on the bottom of my MMI screen.

When I checked, I had the same symptoms as the OP; 'Telephone Not installed' messages on the MMI screen and 'Cannot be reached' messages in VCDS for Address 77.

Lifted the carpet and no signs of water ingress; opened the ECU case but no visible issues. But had to fix it by replacing the unit with a cheap eBay replacement.

Julian

The original Bluetooth phone ECU in A8s was the 'Handyvorb2'; latterly I believe the 'BTA' [aka RSAP unit] was used instead.

The BTA is a 'better' unit as it uses an external aerial rather than the phone for reception, but although the Handyvorb2 and BTA are 'sort of' plug compatible, you can't easily replace the Handyvorb2 with the BTA as you won't have the external aerial you need.

Handyvorb2 HW part number is 4E0 862 335; it has 3 connections - electrical, optical & BT aerial.
BTA HW part number is 4F1 862 335; it has 4 conections - electrical, optical, BT aerial & external aerial.

Julian