Recently the audio sounds off from the iPod/iPhone connected with a 3.5mm cable, the music is distorted and missing low and high frequencies. This happens 80% of the time, which is really weird. Dealer has never seen this issue before...

The dealer initially replaced the Aux In input/socket but it's still not working. The dealer mentioned that they may need to replace a audio module, which is really expensive plus labor. Do you have any ideas what it could be? They don't think it's a grounding issue based on the new Aux In being installed. I'm at a loss after searching every thread.

I understand that the Aux In goes directly into the head unit because I don't have bluetooth or usb in my car.

 

Have you tried a different iPod/iPhone? My 4 developed a weird problem a few months back where the analog output from the phone sounded like what you're describing. I restored the phone and it fixed the problem. If you have tried other devices then nevermind me!

 

Yes, I tried 3 different devices (iPhone 4, iPod Nano and dealer's Android phone) and 2 different 3.5mm cables. Same result on all. Funny thing is that it was working fine for 5 min this morning and then the issue persisted and was replicated at the dealer.

They mentioned that it could be the cable (fiber optic?) going from the aux in jack to the headunit. CD Player and Radio work perfectly.

 

Try turning the volume of your player down to about 60-70%. Any time you're playing over analog, then you also have the problem of amplifing something that has already been amplified you're gonna create distortion. If 60-70% volume helps, keep adjusting with it.

 

I tried that without success. When plugged in, the music sounds more like the low and high frequencies are at very low volumes but it's never consistent. Just sounds plain awful.

 

Since you don't have bluetooth, it is regular wires leading to the headunit (with bluetooth the aux-in jack wires lead to the ULF module under the driver seat, then the ULF connects to the fiber optic MOST bus ring).

Now, I typically have a Sirius radio plugged into my aux in, sounds great. I tried my ipod touch 4th gen last week for the first time and it sounds TERRIBLE like you describe, hissy and nasty.

The only thing you can try to adjust is the aux input volume (on the head unit, middle soft button).

 

Not sure if this is the issue. I noticed with an iPhone 4 and 4S I would get a nasty hiss out of the headphone jack on the phone. After some Googling, this appears to be a known issue with certain BMW's & Mini's and the iPhone 4/4S (no hiss on an iPhone 5 btw).

I bought a cheap $2 cable from a guy on ebay (looks like it's $4.61 now) and NO HISS!

http://www.ebay.com/itm/New-Black-US...item20ccc8219b

Since the original poster mentioned trying an Android phone, I'm not sure he's having he same issue I did.

 

I'm having issues with my audio jack as well. It hasn't worked properly since the day I got it (bought the car new). It sounds great if I hold and apply pressure to the cable when plugged in, but as soon as I take my hand away, you hear one half of the car lose most of its sound. It's really annoying. I've tried my phone, my ipod, and my ipad, each with three different cables. I'm due for my first oil change in 500 miles and I'm going to ask the dealer to look at it.

 

BJM, I have same exact issue on 2010 MCS... What was result of your visit to the dealer? Dd it get sorted? If so, what was the culprit?
Thanks!

 

Had this prob since new, hiss & low volume unless you get the source in a certain position. The slightest movement & it's back.

Dealer dismissed it as a problem with my cable, though it worked fine in another car.

I just stopped using it, it's been years since. I now burn mp3 CDs instead.

Sometimes I wish I had a USB port instead