'09 M3 - No SOS/AUX/USB/Bluetooth

[nsogiba]

As the title suggests I'm having issues with my '09 M3 with CIC/Idrive.

SOS Malfunction



Aux in center console doesn't play when connected to Android via 3.5mm cable. Also, the volume for the AUX in Idrive isn't able to be moved from zero.



USB in center console has no power (verified with multiple cables)

Bluetooth not activated (just spins, trying to connect via Idrive).

The radio plays normally via FM/AM stations, but it's annoying not having Bluetooth for phone calls and being able to stream music through my bluetooth adapter via AUX.

I have tried to use a fiber optic jumper to bypass certain modules on the MOST ring including the TCU in the trunk on the right, the satellite module in the trunk on the left, and a random mystery MOST connector that was wrapped in foam.







I did also remove the head unit and visually inspect the MOST plug - there are long flashes, indicating it's getting the fiber optic signal.

I'm at a loss here...any other modules that could be causing the system to break down? Are all these failures related?

[Scrippy]

Where is your amp? I'm used to seeing the silver individual amp. That most connection wrapped in foam is either your amp MOST or a future for CD changer. Either way it should be loop terminated or plugged into a module. Check your VO for CD changer pre wire option. The other issues sound like coding that's wrong. When AUX volume doesn't show it is because of MULF2 coding being wrong or module is busted. Do you have a coding cable and WinKFP?

[nsogiba]

Originally Posted by Scrippy

Where is your amp? I'm used to seeing the silver individual amp. That most connection wrapped in foam is either your amp MOST or a future for CD changer. Either way it should be loop terminated or plugged into a module. Check your VO for CD changer pre wire option. The other issues sound like coding that's wrong. When AUX volume doesn't show it is because of MULF2 coding being wrong or module is busted. Do you have a coding cable and WinKFP?

The random MOST connection definitely looks like preparation for a CD changer or something else that I'm not familiar with. It was not loop terminated, maybe that's part of the problem?

Here's the crazy part, I found another MOST plug on the module under the TCU and plugged in the loop. The SOS error went away and the Bluetooth phone connection started working again. Great success! However, AUX and USB are still inop.



I do have a used TCU on the way to see if that will rectify anything.

Where is the MULF2 module located? I don't have WinKFP, I do have a K-CAN cable (OBD2 to USB) that I used to MHD flash my 335i.

Sorry, I'm a nuts and bolts guy, not an electrons guy.

[nsogiba]

It stinks when you find these threads asking for help but never providing the fix, so I'm going to contribute some good karma...

My issue ended up being the MULF2 module, on the trunk floor on the right, under the TCU module. A $50 replacement on ebay did the trick and didn't need to be coded.

Originally Posted by nsogiba

When I purchased the car, I had some minor but annoying issues:

SOS - Inactive Warning
Bluetooth not working
USB and AUX plugs in center armrest had no power/signal

It was frustrating not being able to make phone calls through the car's speakers, and not being able to play music.

I'm not an electronics guy but through some research found that any interruption in the MOST fiber optic system will cause multiple failures. Similar to the Christmas light bulb effect, when one dies they all die. My symptoms weren't that bad, but I did purchase a fiber optic loop jumper that allowed me to bypass modules one by one until I stopped having problems.

Once I jumped the MULF2 module (located on the trunk floor on the right side, under the TCU module), the Bluetooth came back and I was able to pair my phone. The SOS warning also went away. Success!





That meant that there was definitely an issue with the MULF2 module, so I found a used one on ebay for $50 and installed it. The SOS warning was permanently gone, the Bluetooth capability was restored, and the biggest victory was the AUX coming back. It was so motivating seeing the AUX volume bar moving, rather than being stuck at zero like it had been for so long. The USB port in the armrest also had power again.

The only thing that was left was the 12V power port in front of the shifter - again, no power. This is a simple power port that doesn't use any modules for activation, just a simple fused circuit.

I dug open the glove box to find the fuse panel...



Consulted the diagram which was neatly folded in the cover



Found Fuse 08, which controls accessory power



And removed it for a closer look, compared to a known good 20A fuse.





My assumption is that at some point someone dropped a coin into that power port and shorted it, which blew the fuse.

[tdott]

Nice,

Another option would have been to upgrade to a Combox and get rid of the TCU/MULF and that would give you bluetooth streaming and other features. But it would have required some re-wiring and coding.

[nsogiba]

Originally Posted by tdott

Nice,

Another option would have been to upgrade to a Combox and get rid of the TCU/MULF and that would give you bluetooth streaming and other features. But it would have required some re-wiring and coding.

Good point. If I ever get tired of the current setup I may look into that, but between the coding and cost to buy the combox setup, it didn't seem worth it at the time.

What other features does combox give you?

[Scrippy]

Originally Posted by nsogiba

Good point. If I ever get tired of the current setup I may look into that, but between the coding and cost to buy the combox setup, it didn't seem worth it at the time.

What other features does combox give you?

APPS, album art with music, Video options 6nr/roku/Apple TV, connected drive, Mlap Timer, Multiple phone BT pairing, BMW services w/subscription w/newest combox only. If all you care about is Bluetooth music you're good already though as no sound improvements will be had. Because there is no album art on BT even with combox. Album art is only good via USB or snap in (plugged in) on combox. I had TCU & MulfII and only went to combox for 6nr videos from my old iPhone 4s and album art because I'm an obsessive techie.

[cantonknees]

Stumbled on this thread, wanted to say great detective/troubleshooting work

[peterc05]

Having the same exact issue on a car I just purchased. Can I use something like this?

[nsogiba]

Originally Posted by peterc05

Having the same exact issue on a car I just purchased. Can I use something like this?

The replacement module for my car was about half the price of that adapter.

[peterc05]

Originally Posted by nsogiba

The replacement module for my car was about half the price of that adapter.

I ended up just buying one those Bluetooth to fm radio transmitters for $20 bucks. 🤷*♂️ works for me

[micdev42]

Originally Posted by nsogiba

It stinks when you find these threads asking for help but never providing the fix, so I'm going to contribute some good karma...

My issue ended up being the MULF2 module, on the trunk floor on the right, under the TCU module. A $50 replacement on ebay did the trick and didn't need to be coded.

I've just stumbled across this thread. Thanks for taking the time to post your experiences: karma is on its way!
I'm in UK and have a E93 325i where the AUX is greyed out when I try to select it. Plugging in a 3.5mm cable doesn't work. USB is dead. At least with your findings I have something to go on. I'll post back when I find out what's going on.
Cheers
Michael