BMW bulletin B840121
What it saysTELEMATICS UNIT DEACTIVATION DUE TO 3G CELLULAR TECHNOLOGY DISCONTINUATION: The discontinuation of 3G cellular communication for Combox, TCB 3G and ATM 3G (Telematics ControlModule) can no longer be supported by… NHTSA’s full summary ↓
BMW filed this with NHTSA as a service bulletin dated May 1, 2021, received Aug 23, 2021, about the equipment. It names 58 model years (2016–2021). 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.
Get the next BMW bulletin for your model by email Weekly, only when something new is filed. Nothing else; one-click unsubscribe.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationTELEMATICS UNIT DEACTIVATION DUE TO 3G CELLULAR TECHNOLOGY DISCONTINUATION: The discontinuation of 3G cellular communication for Combox, TCB 3G and ATM 3G (Telematics ControlModule) can no longer be supported by the cellular network provider starting February 2022.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| B840121 | Service bulletin | May 1, 2021 | 10200487 | not found |
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.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
Find the electrical for the 2021 2 Series →Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
Model years it names
Source: as the manufacturer filed themand 17 more on this site: 2017 BMW X5, 2016 BMW X5, 2019 BMW X6, 2018 BMW X6, 2017 BMW X6, 2016 BMW X6, 2016 BMW Z4, 2021 BMW i3, 2020 BMW i3, 2019 BMW i3, 2018 BMW i3, 2017 BMW i3, 2016 BMW i3, 2020 BMW i8, 2019 BMW i8, 2017 BMW i8, 2016 BMW i8.
Also filed against model years this site has no page for: 2016 BMW B7 Alpina.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Email me new BMW bulletins for one of these models
A weekly email, sent only in a week when BMW files something new with NHTSA for the model you pick — service bulletins, campaigns, warranty extensions, over-the-air notices, every model year. Nothing else is sent; one-click unsubscribe in every message. Separate from recall alerts.
What owners reported
Source: NHTSA complaint databaseOwners of the 57 model years this bulletin names have filed 1,912 complaints with NHTSA since 2015.
Very disappointing experience. Hatch back with "kick" open feature randomly hits me on the head while I AM moving things around in the trunk space as I move side to side to rearrange items. AM told I would need to spend $250 to de-activate the "kick open" feature.
2018 BMW X1 · Equipment · filed with NHTSA Mar 12, 2018 · ODI 11078705
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 equipment
Source: same model, same component group31 other manufacturer communications filed against these BMW models under the same component group (equipment), newest first. The eight newest are listed; the rest are on the BMW list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| B010122 | Service bulletin | Jan 21, 2026 | With the court's FINAL approval, BMW of North America, LLC (BMW NA) has entered into a nationwide settlement with the plaintiffs in the foll… |
| B011323 | Service bulletin | Mar 12, 2025 | BMW of North America, LLC (BMW NA) has a nationwide settlement with the plaintiffs in the following class action: Brightk Consulting, Inc.… |
| B610124 | Service bulletin | Jan 6, 2025 | When driving over rough surfaces, a low-frequency rattling noise can be heard inside the vehicle's cabin. The noise typically sounds as tho… |
| B610615 | Service bulletin | Dec 18, 2024 | Washer Fluid Reservoir Rattles While Driving on Rough Roads. Rattling noises heard from vicinity of glove box. The windshield washer reservo… |
| B650121 | Service bulletin | Jun 12, 2024 | SPORADIC FAILURE OR CRACKING NOISE IN BASS SPEAKERS: No Bass or a cracking noise can be heard from the bass speakers. |
| B650421 | Service bulletin | Jun 4, 2024 | RETROFIT SATELLITE RADIO (OPTION CODE SA655): The affected vehicles were produced with Preparation BMW Satellite Radio (option code SA 693)… |
| B511520 | Service bulletin | Mar 21, 2024 | WIND NOISE FROM ENGINE BULKHEAD: A wind noise can be heard when driving at highway speeds from the area around the lower windshield. Imprope… |
| B640424 | Service bulletin | Mar 8, 2024 | 1. The center air vent on the left (a) is closed. All other air vents on the left side then only blow cold air intothe passenger area. OR… |
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 B840121 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 B840121 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 B840121 cover?
The manufacturer filed it against 58 model years: 2021 BMW 2 Series, 2020 BMW 2 Series, 2019 BMW 2 Series, 2018 BMW 2 Series, 2017 BMW 2 Series, 2016 BMW 2 Series and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.