BMW bulletin B521723
What it saysCustomer states one of the front seats is inoperative. NHTSA’s full summary ↓
BMW filed this with NHTSA as a service bulletin dated Jan 2, 2024, received Jan 3, 2024, about the seats — 2 documents under this number. It names 31 model years (2016–2024). 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.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationCustomer states one of the front seats is inoperative. The seat heater and power supply are inoperative .During the vehicle test, the seat module does not respond. The power supply fuse for the seat module is found to have blown.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| B521723 | Service bulletin | Jan 2, 2024 | 10249023 | PDF, 2,797 KB |
| B521723 | Service bulletin | Dec 11, 2023 | 10247576 | not found |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 52 20 2 697 913 | Felt Tape Sublet as needed | — | eBay Motors → |
Read by machine from the document NHTSA serves (4 pages), read Sep 30, 2026. A part number is shown only where it matches BMW’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. 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. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themAlso filed against model years this site has no page for: 2020 BMW 330E; 2023 BMW M4 GT4.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 29 model years this bulletin names have filed 777 complaints with NHTSA since 2015. 133 of them name Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
The contact owns a 2019 BMW X1. The contact stated that the emergency call error light illuminated the instrument panel. In December of 2024, the contact received notification regarding an extended warranty coverage for the battery to be replaced. The contact was unable to immediately take the vehicle to the dealer due to other reasons.
2019 BMW X1 · Electrical System · filed with NHTSA Mar 12, 2025 · ODI 11647914
The contact owns a 2022 BMW 430I. The contact received notification of NHTSA Campaign Number: 26V056000 (Electrical System). The dealer was contacted, and the contact was informed that the part for the recall repair would be unavailable for six weeks. The manufacturer was not contacted. The contact had not experienced a failure
2022 BMW 4 Series · Electrical System · filed with NHTSA Aug 10, 2026 · ODI 11755887
Error msg indicating “secure vehicle against rolling” appeared. Also, “Transmission: Secure vehicle with parking brake when stopped. Consult service center.” Apparently from many comments from other BMW owners and mechanics the issue is common and is related to an inexpensive spring that has broken in the shifter box.
2017 BMW X1 · Electrical System · filed with NHTSA Dec 22, 2021 · ODI 11444699
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the seats
Source: same model, same component group6 other manufacturer communications filed against these BMW models under the same component group (seats), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| B520120 | Service bulletin | Jun 27, 2026 | GROANING NOISE FROM TRIM APERTURE ON THE FRONT SEAT: When getting in or out of the vehicle a groaning noise can be heard from the opening… |
| B521225 | Service bulletin | Sep 18, 2025 | A clicking noise can be heard from one or both front seat backrests. This noise is heard when leaning against the backrest of the seat or wh… |
| B521125 | Service bulletin | Aug 21, 2025 | If the seat ventilation is deactivated via the switch or due to parking the vehicle, the fans in the seat cushionor under the seat cushion s… |
| B060425 | Other | Jan 22, 2025 | FITTINGS RETURN |
| B520121 | Service bulletin | Aug 1, 2023 | SEAT FAILS TO INITIALIZE DUE TO MISSING END STOP: Front seat will not calibrate/initialize. |
| B520723 | Service bulletin | Jun 1, 2023 | The front seat heating does not heat up after vehicle departure with the climate control in the automatic mode. |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for BMW, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is BMW B521723 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 B521723 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. Every BMW warranty extension on file lists the ones BMW has filed.
Which vehicles does B521723 cover?
The manufacturer filed it against 31 model years: 2024 BMW 3 Series, 2023 BMW 3 Series, 2022 BMW 3 Series, 2021 BMW 3 Series, 2020 BMW 3 Series, 2019 BMW 3 Series and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.