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Old 03-25-2013, 07:40 PM
csmcphail csmcphail is offline
2011 X3 35i
Location: Upstate NY
Join Date: Jul 2012
Posts: 34
Mein Auto: 2011 X3 35i
Exclamation X3 35i (N55) Low Speed Hesitation Revised and Final Fix

SI B24 02 12 did not work for me. See email below, which resulted in a productive exchange with an excellent Gault BMW customer service rep (Dave Belknapp) and a BMW field engineering rep. The more current service bulletin SI B12 09 12 was performed. I took our car on an urban road trip and the throttle now acts more like a mechanical more 'requests to the department of engines and transmissions for consideration of acceleration needs'. In my opinion, the Nov 2012 fix described in the attached bulletin SI B12 09 12 works indeed!

**************************HISTORY***************** *******
Ref: VIN: xxx, Production #yyy, Miles appx:11,600

Dear BMW Customer Relations:

My wife and I love many aspects of our 2011 X3 35i. We had an absolute blast at the Performance Center Delivery in the Fall of 2011!

There is a significant, persistent issue that has not been resolved to our satisfaction, despite 2 service appointments. Throttle behavior at low speed is unpredictable and erratic to a degree that it keeps me on edge. My wife now looks for reasons to not drive the car. It is very difficult for either of us to perform gentle throttle manipulations at low speed without the car either momentarily hesitating or shooting off like a rocket. Likewise, when slowing down and then resuming posted speeds in situations like slowing for a traffic light transitioning from red to green, there is a similar difficulty predicting what will result from gentle throttle inputs. In other scenarios, the engine is a marvelous and velvety smooth beast.

Back in April 2012, we had the following update performed at Gault BMW in Endicott NY:
“A new software calibration was just released for this engine:
SI B24 02 12
N52T/N55 with 8HP45: Delay in Engine Response
F25 with either N52T or N55 engines and 8HP45 transmission up to 1/16/2012
When slowing down to lower suburban road speeds and then reaccelerating, a delay in engine response may be experienced
Unfavorable EGS and DME software calibration
Program the vehicle using ISTA/P 2.46.0 or higher”

In October, we took the car back to Gault BMW. The friendly service staff and technicians could not find any codes and confirmed the SW update was correctly performed back in April. Again, they were very professional and supportive, but were unable to solve the problem. We’ve been Acura customers since the mid-1990’s and decided to give BMW a try last year. There is so much to love about our X3, but this problem is a definite sore spot. We would greatly appreciate if BMW would get to the root cause of this problem.


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