A8 D3 Bluetooth problem
 

Good evening,

Hopefully I can get some guidance on a retrofit I've just done on my 2006 A8.

I've removed the existing faulty Motorola 4e086233c fixed phone module and fitted a 4E0 862 335 (HW13) Bluetooth unit I got from an Audi parts specialist. The required wires from the Motorola plug were removed and fitted into the 52 pin plug that came with the Bluetooth unit.

33 Diagnostics - Pin 14.
42 Mic + - Pin 11.
41 Mic gnd - Pin 12.
15 Gnd - Pin 10.
16 Gnd - Pin 2.
35 +12v - Pin 1.

Once this was done I plugged the 52 pin plug in the Bluetooth unit along with the MOST fiber optic plug and the Bluetooth aerial. I then replaced the fuse and switched the ignition on. MMI Screen popped up for a few seconds and then went blank. Checked feed on pins 1 and 2 of Bluetooth unit which showed a healthly 12.7 volts. Removed MOST plug and installed Audi bypass link and everything fired up fine which indicated a problem with the newly fitted Bluetooth module. Refitted MOST plug into unit and switched ignition on, again screen pops up for a few seconds and then blank.

Fired up VCDS and tried opening up module 77 telephone but no connection. Then ran optic test which showed electrical and optical error with 77 - Telephone module.

Am I missing something simple or does it indeed look like the unit purchased from the specialist is defective? When I enquired before purchasing they stated it had been tested and also comes with a 2 week warranty.

MMI is software version 5570 and everything work fine when the Bluetooth unit is bypassed via a MOST link. Bluetooth unit is software version 4E0 910 336F

Thanks in advance for any guidance/help.

Regards

Ben.

Welcome along to the forum -

It would be good if you could introduce yourself and you car in the relevant section - the folks here like to see pictures of the cars too.

I'm by no means an expert, but have you altered the coding using VAGcom to code out the armrest handset and to code in the bluetooth module so that the car knows it has one? Might be what it is. . . . +++

Hi Bendy,
Looks ike you used the correct pinouts as they are the same as this thread...
http://forum.a8parts.co.uk/showthread.php?t=908
which a few of us used, including me (but it was years ago)
If you are sure the electric pins were swapped to the correct posisitions, then I would say it's a faulty unit as it is quite a simple retrofit, the hardest thing is getting under the carpet for the physical swap out. It might be worth checking pins 1 & 2 for 12V as if any unit on the MOST bus doesn't power up, the whole MOST bus is down (no bypass feature).

Thanks for the welcome. I have only just got the car so will get some pictures and an introduction posted soon.

Took the carpet and the front passenger seat out so no real problems with access.

Pin1 and 2 has a healthy 12.8v on it when the ignition is on and the MOST bus is fine if I unplug it from the Bluetooth module and plug in a MOST loop, with the radio, cd, satnav, DAB, Bose amp all working correctly.

When I unplug the loop and plug the MOST bus back into the Bluetooth unit the system reboots but the screen just shows Audi MMI intro and then goes black. If you reset the MMI (using Tel, middle, top right buttons together) again it starts up with the intro screen and then just black, indicating the MOST bus in incomplete.

Got a response from the seller saying it was definitely working but that he would take it back if I couldn't get it to work.

The only other thing I can think of is that maybe the MOST diagnostic wire is defective, pin 14. Is there any simple way of testing this wire (voltage, frequency etc) ?

many thanks

Ben

With the unit plugged in and powered up but with the MOST unplugged, does the unit emit a red light from the MOST socket?

Tested the unit with a lab 12v power supply.

12.3v to pin 1 and ground to Pin 2.

Turned the supply on but nothing emitting from the MOST socket.

It also wasn't emitting anything when it was plugged into the car yesterday with the MOST cable removed.

I'm going to return it for a refund I think.

Regards

Ben

Sounds dead to me. Go for the refund.

Just to add, when you get a working unit in you'll next have to get component protection removed for it to fully work.

I don't believe phone modules have CP....

Bose amp does, so does CD changer, but phone / TV / Radio / AMI are CP free I believe.

I second that as I had no issues with CP when I did mine+++

Good to know there's no CP on that module +++