[heffs550]

Hi, I was wondering if anyone's had experience with SIB 640211, and what it's supposed to do. I couldn't seem to get to the BMW service bulletin site w/o a subscription.

I had the oil changed in my 2011 550 Automatic last week and asked whether they were any software updates for my car. I mentioned a couple of the common issues, the lag in throttle response, especially in highway merging situations, and the rear vents always blowing cold air unless the outside temp is below freezing.

The service report indicated no SIB for the throttle response (though I've since read here there's another SIB that's supposed to be a remedy), but SIB 640211 was referenced for the rear vent issue.

Anyway, when I got the car back I immediately noticed a BIG difference in the throttle response - basically transformed the car. I kind of liked it at first, but after a couple of days noticed the car seems to stumble or studder slightly when re-applying the gas lightly after coasting with my foot off the gas, and in traffic circles at low speed and light throttle. I noticed this very infrequently before on the highway only, but now it happens a few times a day. I'm not sure exactly what's happening - engine or transmission - but the car shimmies for a second or two as if it's deciding between states.

The suspension settings also seem to have changed. Road imperfections and other vibrations seem to be transmitted to the cockpit much more directly than before (like run-flats times 5). I'm still trying to convince myself this isn't imagined, because I find it hard to believe they could and would change the fundamental ride characteristics that much with software.

The computer-recommended oil change will be coming up in a couple of months (18000+ miles), and I'll try it out until then, but at this point I'm inclined to request a reset back to the original settings (if that's possible), or a different SIB overwrite.

Thanks for any insight!

[lindros2]

Not sure you can ever go back/downgrade software.

My rear vents (non-4-zone) are useless. I nearly traded my car in 2011 over this issue, but $8k was too much to make up for a $500 slip-up in ordering (thanks BMW dealers).