Owners of BMW 550iA and 650i models built between September 2005 and February 2007 may comment about a host of different transmission shift complaints.
Among the problems that might be reported are an intermittent harsh 4-3, 3-2 or 2-1 downshift when coming to a stop under light brake pedal application; a jolt or jerk when re-accelerating after a coastdown; or a juddering sensation when gently accelerating at engine speeds below 2000 rpm. The car maker attributes the shift woes to software issues in the DME and EGS software.
Reprogramming the modules with updated calibrations is the only surefire fix.
Check with a dealer for the specifics of the flash.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via email at [email protected].