Honda Accord Hybrid 2018–2020 — technical service bulletin
Bulletin A21-053 · NHTSA communication 10198766 · issued Jun 29, 2021
Technical service bulletin
communication type
Electrical System
component
2018–2020
model years
3
vehicle entries
Official summary
Service Bulletin - There is a booming or humming noise coming from the speakers while driving at highway speeds.
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.