TSB B540421 — BMW Service bulletin
B540421 is a service bulletin on file with NHTSA for 2 BMW models, 2000–2023 model years, filed and re-filed as 2 documents. A TSB is factory repair guidance, not a recall — the repair is not automatically free.
What the bulletin says. The front sunroof glass seal has shrunk, creating a gap which can cause wind noise or excess water entry.
NHTSA's own summary of the document, quoted from the public manufacturer-communications file.
Vehicles and model years B540421 names
| Vehicle | Model years |
|---|---|
| BMW X3 | 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2021, 2023 |
| BMW X5 | 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 |
Every document filed under B540421
Manufacturers re-issue a bulletin as the repair changes, and file separate copies for technicians and for owners. All of them carry the same number.
| Document ID | Filed | Type |
|---|---|---|
| B540421 | October 18, 2023 | Service bulletin |
| B540421 | September 1, 2022 | Service bulletin |
What B540421 covers
Body & structure, Visibility & wipers — the component vocabulary NHTSA files this communication under.
Questions buyers ask
What is TSB B540421?
B540421 is a service bulletin filed with NHTSA by BMW, covering 2 BMW models across the 2000–2023 model years. NHTSA's summary reads: The front sunroof glass seal has shrunk, creating a gap which can cause wind noise or excess water entry.
Which vehicles does B540421 cover?
NHTSA's file names BMW X3 (2004–2019, 2021, 2023); BMW X5 (2000–2018). A bulletin number can be re-issued against more vehicles later, so check the model-year list on this page against your own.
Is TSB B540421 a recall, and is the repair free?
No. B540421 is repair guidance the manufacturer sent its dealers, not a safety defect finding. You pay for the work unless the vehicle is still under warranty. Recall repairs, by contrast, are always free.
How do I get the full text of B540421?
Take the document ID to a dealer's service desk, or search NHTSA's manufacturer-communications records. This page carries every document ID filed under B540421, its date, and NHTSA's own summary from the public file.
Every number on this page is a count of records in the federal complaint, recall, and investigation files published by NHTSA's Office of Defects Investigation. This page lists only what NHTSA's manufacturer-communications file records under B540421. Check any specific vehicle's open recalls by VIN at nhtsa.gov/recalls.