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 +++

Thanks for everyone's input.

Going to return the unit then try and source one locally, so I can see it working before purchasing.

Awesome forum and I'll get my profile/intro done asap +++

If you're going to try and get another unit, can I suggest you try and get a A8 BlueTooth phone unit part number 4F1 862 335 instead of 4E0 862 335.

They both share the revised electrical connections you've sorted out but the 4F1 unit [known as a 'BTA'] is a 'better fit' than the more often seen 4E0 unit [known as a 'Handyvorb2'].

The 4F1 unit has an extra connection that lets you use the roof aerial connection that the Motorola unit used. The 4E0 unit makes use of the phone's aerial. The 4F1 potentially gives you better reception with the roof mounted amplified aerial.

Julian

Hi all,

Managed to get another 4e0 unit but am a bit worried about plugging the thing in after the first unit didn't power up.

With the unit off the car can I simply apply 12v to pin 1 and ground to pin 2 and check the red light blinks on the MOST output first?

Also am I correct in thinking that pin 10 and pin 2 should have continuity as they are both off Terminal 31?

Lastly how does the diagnostic wire work? What sort of signal does it send to the Bluetooth unit or does the unit send a signal back. I'm sure when I was checking with a digital voltmeter between diagnostic wire and ground I was getting 12v. Is that correct?

Many thanks for all the help

Ben..

Hi Ben,

When I've tested units on the bench the most optical does blink 3 times then goes off. A good indication that the module works.

As for continuity test, pin 2 to earth yes, not sure about pin 10 as that looks like it goes to the connection in the armrest.

Again, not sure how the diagnostic wire works. I've not looked into it.

+++

Cheers Matt,

Powered up the unit I received today using a bench power supply, Pin 1 connected to 12.5vdc and Pin 2 to 0v return. Switched on the power supply and....... nothing !!! Double checked 12v at the pins.

No blinks from the MOST optical and the unit isn't even pulling any current.

2nd unit off eBay that's been DOA. Currently arranging for it to go back.

I give up for the time being, as I'm getting the right hump with people advertising working units when they obviously aren't and me wasting my time.

Sorry to hear this Ben, what bad luck you've had.

I haven't 'played' myself, but the diagnostic wire is part of the 'Ring Diagnosis' circuit of the MOST connected MMI ECUs. The diagnosis wires from the ECUs are connected in a 'star' together with the Gateway.

When a diagnosis is requested, the Gateway pulses the diagnosis connection to 'wake up' the ECUs which send test signals on the optical loop.

Don't know what the voltage levels are though, sorry ...

Julian

Thanks Julian,

Update - Told the seller I wanted their return address details and that I'd raised a returns request through EBay, to find that he fully refunded me the next hour. They didn't even send return details !!!!