Mazda CX-3 2016–2020 — technical service bulletin
Bulletin 04-002-21-3809 · NHTSA communication 10198568 · issued Jun 4, 2021
Technical service bulletin
communication type
Service Brakes
component
2016–2020
model years
17
vehicle entries
Official summary
Some vehicles equipped with electric parking brake (EPB) may exhibit a grinding noise from the rear brakes when braking. This may be caused by the rear brake pads not having the capability to remove the rust from the rear brake discs. The red rust accumulated on the discs is exposed to high temperatures during braking, and consequently the rust turns black. As the black rust is too hard to be removed by the brake pads, the rust progress is accelerated, resulting in the grinding noise.
Vehicles covered
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.