Service bulletins for the 2021 BMW M4
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.
72 on file from NHTSA, as of 2026-10-19.
By type
By component
Only bulletins with component: Axle are shown. Show all
| B340921 | 2021-11-08. Service bulletin. POWER TRAIN:AXLE ASSEMBLY. A turbine-like noise can be heard from the rear axle while deceleration during the first 300 miles of operationwhen braking from low speed. |
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The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.