BMW bulletin B840525
What it saysSITUATION After the telematics module (TCB4) has been replaced, the replacement part control unit is not accepted byISTA. NHTSA’s full summary ↓
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.
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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 | At NHTSA |
|---|---|---|---|---|
| B840525 | Service bulletin | Aug 13, 2025 | 11022119 | PDF, 618 KB |
What the document itself lists
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 84 99 000 | Worktime to perform the conversion “Replacement of WAVE11 to WAVE01” | 1 FRU |
Read by machine from the document NHTSA serves (6 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 themA 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 6 model years this bulletin names have filed 102 complaints with NHTSA since 2015. 26 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.
I brought a brand new BMW IX fully electric vehicle in May, 2023. A couple of weeks ago in early September, the “Emergency Call System Malfunction” warning light came on, and I can also smell a chemical burn from the vehicle. I dropped it off to Eastbay BMW in Pleasanton, California. 4350 Rosewood Drive, Pleasanton, California 94588.
2023 BMW iX · Electrical System · filed with NHTSA Sep 28, 2023 · ODI 11547159
I was driving on Single Pedal Drive on a freeway with the 2024 BMW IX, there was a slow down ahead of me. I removed my foot from the pedal and waited for car to slow down, but car didn't slow down enough. Then I slammed the brakes hard, but the brake didn't engage. In fact, brakes were pushed back against my foot.
2024 BMW iX · Electrical System · filed with NHTSA Apr 3, 2025 · ODI 11652449
The contact owns a 2024 BMW 430I. The contact received notification of NHTSA Campaign Number: 26V438000 (Electrical System); however, the part to do the recall repair was not yet available. The manufacturer was contacted, and the contact was informed that the parts were not yet available.
2024 BMW 4 Series · Electrical System · filed with NHTSA Jul 31, 2026 · ODI 11753950
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 electrical system
Source: same model, same component group76 other manufacturer communications filed against these BMW models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the BMW list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| B630526 | Service bulletin | Sep 8, 2026 | After programming the vehicle via ISTA/RSUto I-level …26-03-5xx, customer may reportsome of the interior ambient lighting strips(arrows) may… |
| B610625 | Service bulletin | Aug 31, 2026 | Check Control message: "You can continue driving. Drivetrain” (00029) is displayed. The following fault code is stored in the CCU fault memo… |
| 0061890900 | Service campaign | Aug 27, 2026 | In vehicles equipped with the Roof Function Center “FZD‑21” variant, a quiescent‑current violation mayoccur if the system fails to enter sle… |
| 0034040300 | Service campaign | Aug 20, 2026 | After replacement of the Integrated Braking system (IB)/Power Brake the total distance covered might be lower than when handed over to the w… |
| 0064460200 | Service campaign | Aug 12, 2026 | A faulty electric auxiliary heater may have been installed in the certain vehicles. This could result in the failure of the electric auxilia… |
| B652026 | Service bulletin | Jul 23, 2026 | The Central Information Display (CID) side of the Multifunction Display (MFD) may flicker intermittently. Theflickering manifests itself in… |
| B840226 | Service campaign | Jul 10, 2026 | Once the Telematics Module (TCB2) enters sleep mode, a BMW Data Services trigger for Remote Services… |
| B610126 | Service bulletin | Jun 11, 2026 | SITUATION During vehicle start-up the Secure Element (SE) of the BCP may fail causing communication errors. TheCheck Control message “Drive… |
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 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. Every BMW warranty extension on file lists the ones BMW has filed.
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.