2011 BMW 328xi, Static Heartbeat on Speaker, AUX and USB Problem

tathirk2000 · 04-12-2023, 05:45 PM

Hi everyone. I recently purchased my first car, a 2011 BMW 328xi. One of the things that stopped working was the AUX, and there is a static heartbeat sound coming from the speakers everytime the AMP is connected. I bought a new AMP suspecting old AMP was faulty, but same issue. I read through several of the threads on the forum to try and see if there was a wiring issue or why theres no sound or power output from the AUX and USB in the center armrest.

I checked to see if my car came with a MULF2 module, but my car has a combox instead. Im suspecting there might be a wiring issue, or some module or part of the car isnt getting power from the combox. I came to this conclusion, because when i connect my phone to the AUX, my phone recognizes that AUX and USB is connected, but nothing is being played from the speakers, even at max volume from phone and car. I also figure that my car should have bluetooth functionality since theres a combox and i have the bluetooth buttons, but no such option exists in the car menu. If there is a connection issue, i think that would also explain why theres static from the speakers. Ive read this happens when theres bad ground connection.

Would you guys be able to direct me in the right direction? What do you guys suspect the problem is? If it is wiring, and somethings wrong with combox or ground connection, how should i tackle it? Any info helps, thanks in advance.

konstnn · 04-12-2023, 11:35 PM

Huh similar story here, recently bought 2011 328xi too and USB and AUX are not working, except I don't have static noises. Some said it could be connections and it worked for them after unplugging/plugging in combox connections, but that did not work for me. Also checked fuses. So now I am blaming combox, ordered used from eBay. Would be nice to know if there are other troubleshooting options.

NZE90 · 04-12-2023, 11:53 PM

Would be advisable to check for fault codes before replacing any parts

Serf27 · 04-13-2023, 01:45 AM

I had an e90 with constant static from the speakers when the car “woke up”
I disconnected the radio and connected it back and the noise went away.
Worth a shot.

ptpending · 04-13-2023, 06:40 AM

the 2011 cars can have AUX and USB routed to headunit, and keep combox only for telematics.
And it is well known that connector to radio sometime loose a little and some issues arise
so it is good idea is to remove radio, remove connector and plug it again one time in 12 years of the car lifetime

konstnn · 04-13-2023, 08:47 PM

So here is my update.
First, I tried connections on the radio - no luck. Connections on combox - no luck.
When I disconnected combox I heard a constant heartbeat from speakers, makes me think your issue is either coming from combox or connections to it.
With the new combox (used from eBay) I instantly got the "USB" audio option enabled and the "Phone" option as well. Bonus - Bluetooth is working yay.
Now the AUX, the sound is no good, it is quiet and is only coming from the front speakers. But at least I can hear the sound now and with a little wiggle of AUX connector the sound changes, volume changes, etc. I think the AUX port needs replacement too.

04-12-2023, 05:45 PM	#1
tathirk2000 Registered 0 Rep 1 Posts Drives: 2011 BMW 328xi Join Date: Mar 2023 Location: New York, New York iTrader: (0)	2011 BMW 328xi, Static Heartbeat on Speaker, AUX and USB Problem Hi everyone. I recently purchased my first car, a 2011 BMW 328xi. One of the things that stopped working was the AUX, and there is a static heartbeat sound coming from the speakers everytime the AMP is connected. I bought a new AMP suspecting old AMP was faulty, but same issue. I read through several of the threads on the forum to try and see if there was a wiring issue or why theres no sound or power output from the AUX and USB in the center armrest. I checked to see if my car came with a MULF2 module, but my car has a combox instead. Im suspecting there might be a wiring issue, or some module or part of the car isnt getting power from the combox. I came to this conclusion, because when i connect my phone to the AUX, my phone recognizes that AUX and USB is connected, but nothing is being played from the speakers, even at max volume from phone and car. I also figure that my car should have bluetooth functionality since theres a combox and i have the bluetooth buttons, but no such option exists in the car menu. If there is a connection issue, i think that would also explain why theres static from the speakers. Ive read this happens when theres bad ground connection. Would you guys be able to direct me in the right direction? What do you guys suspect the problem is? If it is wiring, and somethings wrong with combox or ground connection, how should i tackle it? Any info helps, thanks in advance.
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04-12-2023, 11:35 PM	#2
konstnn Registered 0 Rep 2 Posts Drives: 2011 328XI Join Date: Apr 2023 Location: Colorado iTrader: (0)	Huh similar story here, recently bought 2011 328xi too and USB and AUX are not working, except I don't have static noises. Some said it could be connections and it worked for them after unplugging/plugging in combox connections, but that did not work for me. Also checked fuses. So now I am blaming combox, ordered used from eBay. Would be nice to know if there are other troubleshooting options.
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04-12-2023, 11:53 PM	#3
NZE90 Lieutenant 277 Rep 428 Posts Drives: 325i Join Date: Nov 2022 Location: Mars iTrader: (0)	Would be advisable to check for fault codes before replacing any parts
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04-13-2023, 01:45 AM	#4
Serf27 Brigadier General 2856 Rep 4,324 Posts Drives: 335i Join Date: Apr 2018 Location: Sitting in a BMW. iTrader: (-1)	I had an e90 with constant static from the speakers when the car “woke up” I disconnected the radio and connected it back and the noise went away. Worth a shot.
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04-13-2023, 06:40 AM	#5
ptpending Colonel 463 Rep 2,773 Posts Drives: e91 Join Date: Dec 2013 Location: Poland iTrader: (1)	the 2011 cars can have AUX and USB routed to headunit, and keep combox only for telematics. And it is well known that connector to radio sometime loose a little and some issues arise so it is good idea is to remove radio, remove connector and plug it again one time in 12 years of the car lifetime __________________ 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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04-13-2023, 08:47 PM	#6
konstnn Registered 0 Rep 2 Posts Drives: 2011 328XI Join Date: Apr 2023 Location: Colorado iTrader: (0)	So here is my update. First, I tried connections on the radio - no luck. Connections on combox - no luck. When I disconnected combox I heard a constant heartbeat from speakers, makes me think your issue is either coming from combox or connections to it. With the new combox (used from eBay) I instantly got the "USB" audio option enabled and the "Phone" option as well. Bonus - Bluetooth is working yay. Now the AUX, the sound is no good, it is quiet and is only coming from the front speakers. But at least I can hear the sound now and with a little wiggle of AUX connector the sound changes, volume changes, etc. I think the AUX port needs replacement too.
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