WenmarOpen by Wenmar Pro

Service bulletin B340921

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10233158
Published by NHTSA2023-03-20
Manufacturer's numberB340921
Manufacturer's date2023-02-01
NHTSA componentSERVICE BRAKES

NHTSA's summary

A turbine-like noise can be heard from the rear axle while deceleration during the first 300 miles of operation when braking from low speed.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Brakes

Vehicles listed
BMW M22016, 2017, 2018, 2019, 2020, 2021, 2022
BMW M32015, 2016, 2017, 2018
BMW M32021, 2022
BMW M42015, 2016, 2017, 2018, 2019, 2020, 2021, 2022

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
21V0620002021-02-10. SERVICE BRAKES, HYDRAULIC:POWER ASSIST:HYDRAULIC; SERVICE BRAKES, HYDRAULIC

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
B0647252025-10-10. Other. Protection Plate Return
B3409212025-01-23. Service bulletin. A turbine-like noise can be heard from the rear axle while deceleration during the first 300 miles of operation when braking from low speed.
B3407142023-11-01. Service bulletin. Functional noises (squealing/honking) when braking shortly before the vehicle comes to a stop. CAUSE Material-
B3601222022-05-16. Service bulletin. After replacing tires and successfully programming the Tire Pressure Monitoring System (TPMS) using the RDC tool to transfer the QR code information on the sidewall, the "back-end" support systems need time to update the new tire information.
SIB3407212021-12-13. Service bulletin. When starting the vehicle vehicle at standstill, various yellow Check Control Messages CCMs appear. ID code 00042: Brake system. Additional notes: Avoid abrupt braking as far as possible. Drive at a moderate speed. Have it checked by your nearest Service Center. ID code 2046: Braking force assistance. Additional notes: Braking force assistance failure. Higher pedal force required for vehicle deceleration. Drive at a moderate speed. Have it checked by your nearest Service Center.
B3410192021-11-08. Service bulletin. Inform the customer during a consultation that the M Compound (standard equipment) and M Carbon Ceramic (optional) brakes are high-performance brake systems which are designed for sporty, dynamic driving styles. As a side effect of the highest possible brake performance, customers are likely to hear noises due to the extremely resilient materials. In the same conversation, inform the customer that his/her braking performance can help ensure that the noises do not occur or disappear quickly.
B3410192021-09-07. Service bulletin. Inform the customer during a consultation that the M Compound (standard equipment) and M Carbon Ceramic (optional) brakes are high-performance brake systems which are designed for sporty, dynamic driving styles. As a side effect of the highest possible brake performance, customers are likely to hear noises due to the extremely resilient materials In the same conversation, inform the customer that his/her braking performance can help ensure that the noises do not occur or disappear quickly.
B5111212021-07-06. Service bulletin. ROOF TRIM STRIP LOOSE AT REAR: The roof trim strip may be loose at the last (rearmost) clip as shown. This can occur on either side of the roof, or on both sides.
B3601212021-05-24. Service bulletin. Diagnosis of Compound Brake System Complaints in M Vehicles: 1. Visible cracks are caused by high thermal stresses during rapid heating and cooling of the brake discs. Braking from high speed with cold brake components (less than 212 degrees F) increases the likelihood of cracks to form.
B3404142021-05-24. Service bulletin. Diagnosis of Compound Brake System Complaints in M Vehicles: 1. Visible cracks are caused by high thermal stresses during rapid heating and cooling of the brake discs. Braking from high speed with cold brake components (less than 212 degrees F) increases the likelihood of cracks to form.