BMW bulletin B520121
BMW filed this with NHTSA as a service bulletin dated Aug 1, 2023, received Mar 15, 2021, about the seats — 3 documents under this number. It names 69 model years (2016–2023). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationSEAT FAILS TO INITIALIZE DUE TO MISSING END STOP: Front seat will not calibrate/initialize.
Documents filed under this number
| Document | Kind | Dated | NHTSA id |
|---|---|---|---|
| B520121 | Service bulletin | Aug 1, 2023 | 10242694 |
| B520121 | Service bulletin | Jun 1, 2021 | 10200234 |
| B520121 | Service bulletin | Feb 1, 2021 | 10188945 |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5; the full text comes from the manufacturer or a dealer. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. Quote it at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themand 4 more model years on this site.
Also filed against model years this site has no page for: 2019 BMW 540D; 2020 BMW 540D; 2020 BMW 640I; 2016 BMW 740LI; 2017 BMW 740LI; 2016 BMW 750LI; 2017 BMW 750LI; 2018 BMW 750LI; 2019 BMW 750LI; 2020 BMW 750LI; 2021 BMW 750LI; 2022 BMW 750LI; 2018 BMW B7 Alpina; 2019 BMW B7 Alpina; 2020 BMW B7 Alpina; 2021 BMW B7 Alpina; 2018 BMW C 400 X; 2021 BMW F 850 GS Adventure; 2017 BMW F800 R; 2022 BMW M5; 2017 BMW M550I; 2021 BMW M760LI; 2022 BMW M760LI; 2018 BMW R Nine T Scrambler; 2017 BMW R1200 RT Police.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Common questions
Source: NHTSA, 49 CFR 579.5Is BMW B520121 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the B520121 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does B520121 cover?
The manufacturer filed it against 69 model years: 2022 BMW 2 Series, 2021 BMW 2 Series, 2020 BMW 2 Series, 2020 BMW 4 Series, 2019 BMW 4 Series, 2018 BMW 4 Series and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.