BMW bulletin B840525
BMW filed this with NHTSA as a service bulletin dated Aug 13, 2025, received Aug 24, 2025, about the electrical system. It names 6 model years (2023–2025). 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 communicationSITUATION After the telematics module (TCB4) has been replaced, the replacement part control unit is not accepted byISTA.
Document filed under this number
| Document | Kind | Dated | NHTSA id |
|---|---|---|---|
| B840525 | Service bulletin | Aug 13, 2025 | 11022119 |
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 themA 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 B840525 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 B840525 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 B840525 cover?
The manufacturer filed it against 6 model years: 2025 BMW 4 Series, 2024 BMW 4 Series, 2023 BMW 4 Series, 2025 BMW iX, 2024 BMW iX, 2023 BMW iX. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.