[dandog96]

Hello all!

Recently purchased my 08 328xi 6-speed and am loving it.
Besides this Aux issue, an ABS sensor, and a valve cover gasket I need to replace, the car is a dream.

My problem with the AUX is that I've tried multiple phones, aux cables, and even a bluetooth adapter, yet when I select AUX on my radio I hear nothing.
There is a little hum / static when I turn the volume up on the car, which tells me that it seems like the amplifier is working at least. Normal radio seems to work fine.

My radio is the BMW professional unit, and my vehicle has the MULF2-HI box in the trunk, as well as a satellite radio module. I've tried checking the connection of the AUX / USB socket and it appears everything is firmly connected.

At this point, I've narrowed it down to either the AUX / USB socket just needing replacement, or my MULF2-HI box. I should note, that despite the car having almost no corrosion, that the MULF2-HI box does seem a bit corroded for some reason, with white oxidation-looking stuff on it for some reason. I've attached a few photos for additional reference.

My question: should I start with replacing the AUX / USB socket, or is there I was I can test and determine that my MULF2-HI box is malfunctioning?

Any help would be appreciated, and if needed here is a list of the multimedia features in my car from a BMW VIN decoder:

Multimedia
S640 Preparation F Tel.Installation Universal
S645 BMW US Radio
S663 Radio BMW Professional
S676 HiFi Speaker System
S693 Preparation BMW Satellite Radio
S694 Provisions For BMW 6 CD Changer
S6FL USB/Audio Interface

[ctuna]

Diagnostics per coding subforum might tell you something.
Standard Tools and Ista D recommended.
You will probably need those to program the New Module to.

[dandog96]

Will I need to reprogram / recode if I order an identical MULF2-HI module off of eBay, per say? I am willing to perform diagnostics / basic coding if needed, but an easy swap sounds nice.

[ctuna]

These modules are all programmable. There is chance if you got it from
a car with the same options that it would work without programming.

[dandog96]

Thanks fo much for your prompt response. I removed the MULF2-HI bracket and got a look at the whole unit, and it is literally CAKED with corrosion. Oddly enough, the rest of the car has very minimal corrosion for an Ohio vehicle. I’ll order another MULF2 and see how it goes.

[dandog96]

Replaced the MULF2-HI unit in my e90 with one I purchased on eBay — everything instantly started working! I made sure to source one from another 2008 328 XI that was similarly optioned.

[sonick]

I've replaced my mulf2 from a random car no idea of the model or package and it worked fine, not sure if mulf2's need coding.

[Kabreti]

Originally Posted by dandog96

Replaced the MULF2-HI unit in my e90 with one I purchased on eBay — everything instantly started working! I made sure to source one from another 2008 328 XI that was similarly optioned.

Hello I'm having the same problem. The radio works fine, I can make phone call over bluetooth. But the AUX and USB do nothing, I can heard noise when I volume up, but if I connect my phone or ipod by 3.5 mm jack but no sound, I try to connect a USB pen drive and I it get power but the radio doesn't show a usb connection.

Do you think is the corrosion in the MULF2-HI?

[ctuna]

Maybe you should actually look at it and or change it out.
No movement occurs without effort.

[Frankenstein_135]

Sorry for the bump, I'm having the exact issues. I have a 2011 (LCI) E91 w/o iDrive, but with the professional radio, satellite radio and USB/Audio interface.

Just to recap the issue, the aux doesn't work. Playing songs from USB is not possible, but the USP port and the 12V socket next to it do charge my phone. Radio works as intended. And there is no error code for SOS calls.

I Checked fuses 14, 15, 18, 19, 27, 42, 56, 63, 13, 59 as they seem related to the audio system. Fuses 18, 19, 56 were not present but the rest seemed good. I plugged in those missing fuses just to rule out any chances, and nothing changed. I verified that I have TCU and MULF2-HI in my trunk.

So like the thread mentioned, my MULF2 likely failed, though I couldn't find any corrosion on the outside. I removed and reconnected all the wires hoping to get it back to life as mentioned in this post, without success.
https://www.e90post.com/forums/showthread.php?t=1568401

So I'm gonna buy a new module this weekend. Hoping someone can find this post and there is a workaround so I can save some $$. If not, I will follow up with my outcome.

[ctuna]

Satellite is more likely than mulf.
sometimes you can tell by which module does not display it's option
on the Radio display or which option is grayed out on the Idrive display
not allowing selection.
Anyway there are multiple threads on how to trouble shoot this.

Fuses that are not present means options that are not present.
If it worked at one time and you did not just buy the car it's likely all
fuses that are suppose be there are there.
Also fuses change across the model years .

You can genraly get these modules pretty cheap on ebay or one of the BMW boards.

[Frankenstein_135]

Originally Posted by Frankenstein_135

Sorry for the bump, I'm having the exact issues. I have a 2011 (LCI) E91 w/o iDrive, but with the professional radio, satellite radio and USB/Audio interface.

Just to recap the issue, the aux doesn't work. Playing songs from USB is not possible, but the USP port and the 12V socket next to it do charge my phone. Radio works as intended. And there is no error code for SOS calls.

I Checked fuses 14, 15, 18, 19, 27, 42, 56, 63, 13, 59 as they seem related to the audio system. Fuses 18, 19, 56 were not present but the rest seemed good. I plugged in those missing fuses just to rule out any chances, and nothing changed. I verified that I have TCU and MULF2-HI in my trunk.

So like the thread mentioned, my MULF2 likely failed, though I couldn't find any corrosion on the outside. I removed and reconnected all the wires hoping to get it back to life as mentioned in this post, without success.
https://www.e90post.com/forums/showthread.php?t=1568401

So I'm gonna buy a new module this weekend. Hoping someone can find this post and there is a workaround so I can save some $$. If not, I will follow up with my outcome.

Update - after I replaced the MULF2 module the problem was resolved. I now can play from Bluetooth and USB. Since the replacement has the exact part #, even though it was a used unit from a pre-LCI car, I did not need to do any coding.