TCU, mulf broken aux+usb

lucek95 · 03-22-2018, 03:43 PM

Hi,
a while ago I asked similar question but this time I spent some time with it and took couple of photos. And prepared myself better for asking questions.

First of all I have S6FL USB/audio interface which should provide me working USB + AUX, right?
My car was built (after vin check) on 11.2007 and I have located the TCU unit in the trunk with one optical loop on the side which after disconnecting is turning of the audio in radio, so I think it was responsible for this to work.

I checked fuses in glovebox, nothing is blown. I replaced the usb/aux unit in armrest. I checked cables (looking allright).

Unfortunately my Usb+aux in armrest is not powered. I have Y cable and my phone is not charging (but is recognizing the cable). After switching to aux I have set it to max volume, also set max volume on the phone, but no result. The phone is iphone X, I tested it with 8 and 5s aswell but nothing seems to be working.

On first photo I have made three circles:

it is radio (without it connected there is no sound)
it looks like two fibres disconnected (no red light in any of them)
it was disconnected hidden in package with other cables (don't know what is this responsible for?)

Above left back mudguard I have unit (read about it, looking like AMP) but I don't know really how to get it out, didn't find any instructional video etc. and I don't really want to break anything.

Thanks for any responses.

ptpending · 03-22-2018, 04:26 PM

you have car made for USA market and these unused wires are for Sirius Radio
you 6FL module(MULF2HIGH) is located behind TCU, under bracket
and as I see rusty bolts near tcu that means that there was water and MULF2HIGH dead and fiber optic loop is removed from it and looped because dead MULF2HIGH block fiber optic communication

lucek95 · 03-22-2018, 04:36 PM

ptp what is your suggestion? should I buy a new mulf2high or try to fix this one? Is there any chance you have any video link / or any link how to test if it is running? The water wasn't necessairly in trunk but there for sure was some moisture. I got the car from my friend, but it wasn't running for like last 4 years and was stored in barn. I'm trying to bring it back to life again and I'd love to have usb/aux running

icon2015 · 04-05-2018, 05:43 PM

Hi there,

Would help a lot if you provide the last 7 digits of your VIN so we can know for sure what options you have on your car.
In my opinion the 3rd fiber connector looks very similar to the cd changer connector.
the the last 2 are used 1 by the TCU and 1 by the MULF.
You should know that all fiber optics terminals must be closed. Either by loop, or by a unit. A faulty unit can cause brake in the fiber optic network.
MULF and TCU use fiber optics to communicate with the car. IF you don't see a red light emitting from them when you put your ignition on , then there is a problem in your fiber optics harness, and you should solve that first.

03-22-2018, 03:43 PM	#1
lucek95 Registered 0 Rep 3 Posts Drives: E92 335 XI Join Date: Mar 2018 Location: Poland iTrader: (0)	TCU, mulf broken aux+usb Hi, a while ago I asked similar question but this time I spent some time with it and took couple of photos. And prepared myself better for asking questions. First of all I have S6FL USB/audio interface which should provide me working USB + AUX, right? My car was built (after vin check) on 11.2007 and I have located the TCU unit in the trunk with one optical loop on the side which after disconnecting is turning of the audio in radio, so I think it was responsible for this to work. I checked fuses in glovebox, nothing is blown. I replaced the usb/aux unit in armrest. I checked cables (looking allright). Unfortunately my Usb+aux in armrest is not powered. I have Y cable and my phone is not charging (but is recognizing the cable). After switching to aux I have set it to max volume, also set max volume on the phone, but no result. The phone is iphone X, I tested it with 8 and 5s aswell but nothing seems to be working. On first photo I have made three circles: it is radio (without it connected there is no sound) it looks like two fibres disconnected (no red light in any of them) it was disconnected hidden in package with other cables (don't know what is this responsible for?) Above left back mudguard I have unit (read about it, looking like AMP) but I don't know really how to get it out, didn't find any instructional video etc. and I don't really want to break anything. Thanks for any responses. Attached Images Last edited by lucek95; 03-22-2018 at 03:49 PM..
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03-22-2018, 04:26 PM	#2
ptpending Colonel 535 Rep 2,934 Posts Drives: e81 Join Date: Dec 2013 Location: Poland iTrader: (1)	you have car made for USA market and these unused wires are for Sirius Radio you 6FL module(MULF2HIGH) is located behind TCU, under bracket and as I see rusty bolts near tcu that means that there was water and MULF2HIGH dead and fiber optic loop is removed from it and looped because dead MULF2HIGH block fiber optic communication __________________ E81 2007 130i 6cylinder Montego blue Retrofits: Harman Kardon, High-beam assistant, Removable tow hitch. Auto-dim folding exterior mirrors. Lumbar support. Perfomance Brakes.
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03-22-2018, 04:36 PM	#3
lucek95 Registered 0 Rep 3 Posts Drives: E92 335 XI Join Date: Mar 2018 Location: Poland iTrader: (0)	ptp what is your suggestion? should I buy a new mulf2high or try to fix this one? Is there any chance you have any video link / or any link how to test if it is running? The water wasn't necessairly in trunk but there for sure was some moisture. I got the car from my friend, but it wasn't running for like last 4 years and was stored in barn. I'm trying to bring it back to life again and I'd love to have usb/aux running
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04-05-2018, 05:43 PM	#4
icon2015 Private First Class 21 Rep 126 Posts Drives: E92 320d ~200 bhp Join Date: Apr 2018 Location: Bucharest iTrader: (0)	Hi there, Would help a lot if you provide the last 7 digits of your VIN so we can know for sure what options you have on your car. In my opinion the 3rd fiber connector looks very similar to the cd changer connector. the the last 2 are used 1 by the TCU and 1 by the MULF. You should know that all fiber optics terminals must be closed. Either by loop, or by a unit. A faulty unit can cause brake in the fiber optic network. MULF and TCU use fiber optics to communicate with the car. IF you don't see a red light emitting from them when you put your ignition on , then there is a problem in your fiber optics harness, and you should solve that first.
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