BMW bulletin B120623
What it saysThe engine malfunction warning is illuminated and one or more of the following faults are stored in theDME: 034D63 - Exhaust switchable cam follower, system: continuous deactivation, maximum number of switchingerrors… NHTSA’s full summary ↓
BMW filed this with NHTSA as a service bulletin dated Sep 20, 2023, received Oct 1, 2023, about the engine. It names 12 model years (2021–2024). 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 communicationThe engine malfunction warning is illuminated and one or more of the following faults are stored in theDME: 034D63 - Exhaust switchable cam follower, system: continuous deactivation, maximum number of switchingerrors exceeded 035601 - Exhaust switchable cam follower 1, electrical: cable break 035604 - Exhaust switchable cam follower 2, electrical: cable break 034BBF - Exhaust switchable cam follower, system: switching errors
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| B120623 | Service bulletin | Sep 20, 2023 | 10242884 | PDF, 150 KB |
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 12 model years this bulletin names have filed 562 complaints with NHTSA since 2015. 78 of them name Engine — 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 am started to lease this car in August 2024. After 2 weeks, the car just halted, unable to move. Luckily this happened in my driveway. It took BMW more than 1 month to repair this. They had to change the combined charging unit with a different part number (upgraded part). At that time the car had roughly 200 miles on the odometer.
2024 BMW X5 · Engine · filed with NHTSA Apr 23, 2024 · ODI 11584824
The contact owns a 2021 BMW X5. The contact stated that as her husband was stopped at a stop light, the vehicle began to rev after he had taken his foot off the brake pedal without warning. Once her husband placed his foot back on the brake pedal, the revving stopped, and her husband was able to resume normal driving.
2021 BMW X5 · Engine · filed with NHTSA Feb 1, 2022 · ODI 11449735
The contact owns a 2021 BMW X7. The contact stated that while driving at 20 MPH and depressing the accelerator pedal, the vehicle went into LIMP Mode. The message "Pull Over and Turn Off Your Car - You Have Lost All the Water In the Radiator" was displayed. The contact was able to pull over to the side of the road.
2021 BMW X7 · Engine · filed with NHTSA Feb 10, 2026 · ODI 11717086
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 engine
Source: same model, same component group58 other manufacturer communications filed against these BMW models under the same component group (engine), newest first. The eight newest are listed; the rest are on the BMW list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 0011320800 | Service campaign | Oct 21, 2026 | The cylinder head cover was not installed correctly at the assembly plant. |
| 0012870600 | Service campaign | Oct 10, 2026 | Due to an implementation error in various OBD diagnostics in the vehicle's control units, in very rare cases itmay happen that stored fault… |
| 1171901000 | Warranty extension | Sep 22, 2026 | The Exhaust Gas Recirculation (EGR) Cooler (with EGR Valve) and the Auxiliary Exhaust Gas Recirculation (EGR) Cooler limited warranty for de… |
| B121126 | Service bulletin | Sep 9, 2026 | Potential customer complaints with no fault codes stored / No MIL displayed. 1. “Rough idle after idling for a longer period of time” 2. “Ve… |
| 0011460700 | Emissions | Aug 26, 2026 | The return springs on the exhaust camshaft followers (switchable rocker arm) may break. |
| B064426 | Other | Aug 22, 2026 | Air Flap Return |
| B130126 | Service campaign | Aug 14, 2026 | Delivery Stop - Exhaust System Gasket |
| 0018030200 | Service campaign | Aug 14, 2026 | An exhaust gas sealing ring between thelower catalytic converter and upper catalyticconverter may be missing (1). |
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 B120623 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 B120623 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 B120623 cover?
The manufacturer filed it against 12 model years: 2024 BMW X5, 2023 BMW X5, 2022 BMW X5, 2021 BMW X5, 2024 BMW X6, 2023 BMW X6 and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.