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      11-16-2012, 09:19 PM   #31
alexwhittemore
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Drives: 2009 Crimson 328i
Join Date: Oct 2012
Location: Los Angeles

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Now, this may be a stupid question, but you've tried using the cable WITHOUT the adapter - with an older model iPod or iPhone, right? There are certainly fake or otherwise ineffective BMW Y cables out there.

Full disclosure, if you're into the technical aspects: the 30pin connector has USB, analog audio out, and two pins (TX/RX) of RS232 serial bus on it (and other pins, but not relevant here). Lightning is its own bus and format, with electronics in the plug to translate to other things like USB. In the case of the 30pin adapter, it has translation chips for USB, RS232, and a DAC to output audio on the aux out.

The Y cable from BWM, rather than doing all the audio and control transmission over USB as in newer Hyundais and the F30s with 'advanced bluetooth' has the aux plug wired straight to the aux out on the 30 pin connector, and a USB-RS232 chip. It presents as a serial port to the computer controlling the show (I'm pretty sure it's embedded linux, definitely running in the MULF unit whatever it is), and the computer sends serial commands for track play/skip/control to the connected iPod.

So needless to say, in the translation from MULF to RS232 chip to RS232 lightning chip to iPhone, there's a LOT of stuff that can go wrong. My theory is that sometimes, if you leave the adapter cable plugged in, the RS232-Lightning chip in the cable remains powered by being plugged into the car, which could put it into an indeterminate state where it can't talk over the lightning bus and thus can't produce good replies to the car's electronics, but it CAN still talk to the car's electronics, confusing the car.

Again, I'm not sure if that's the cause, but that's why I suggest unplugging/replugging stuff arbitrarily. But alas, if you've never tested your Y cable with a normal ipod, there's a lot of chance you simply have a bum Y cable.