BMW M3 2015–2017 — technical service bulletin
Bulletin B520217 · NHTSA communication 10146586 · issued Mar 1, 2017
Technical service bulletin
communication type
Seats
component
2015–2017
model years
6
vehicle entries
Official summary
?SERVICE ACTION: CHECK PUMP FOR BACKREST WIDTH ADJUSTMENT . The backrest width adjustment and, the lumbar support adjustment of the front seats (vehicles without option code 7MA: Competition package) are accomplished by a common air pump. There may be a decrease in pressure in the door-side backrest and /or the lumbar support without any user input. The plug connection between the air pump and the door-side backrest width adjustment or the bottom lumbar support may be leaking.
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.