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Service bulletin 15-003-21-3828

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 id10201776
Published by NHTSA2021-10-02
Manufacturer's number15-003-21-3828
Manufacturer's date2021-09-24
NHTSA componentVISIBILITY; LANE DEPARTURE; ELECTRICAL SYSTEM:ADAS:BLINDSPOT:SOFTWARE; EQUIPMENT ADAPTIVE/MOBILITY

NHTSA's summary

Some vehicles equipped with Blind Spot Monitoring (BSM) may experience a BSM indicator light on the outer door mirror, even if there is no vehicle in the alert (blind spot) area. NOTE: This concern occurs only after a cold start. As the BSM control module temperature rises, the BSM system returns to normal operation. Due to BSM control module production variances, a false detection may occur in some units when the BSM temperature in the control module has not yet reached normal operating temperature. To eliminate this concern, the control logic of the BSM control module has been modified.

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

Driver assistance, Electrical system, Equipment and accessories, Glass, wipers and mirrors, Blind spot detection

Vehicles listed
MAZDA CX-52017, 2018, 2019, 2020, 2021

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

Other bulletins for the same vehicles and component
15-001/222022-02-04. Service bulletin. Some vehicles equipped with Blind Spot Monitoring (BSM) may experience a BSM indicator light on the outer door mirror, even if there is no vehicle in the alert (blind spot) area. NOTE: This concern occurs only after a cold start. As the BSM control module temperature rises, the BSM system returns to normal operation. Due to BSM control module production variances, a false detection may occur in some units when the BSM temperature in the control module has not yet reached normal operating temperature. To eliminate this concern, the control logic of the BSM control module has been modified.
SA-013-182018-04-23. Service bulletin. Some customer's may complain that the blind spot monitoring (BSM) is not operating, and the key ON bulb check is OK with no DTCs stored in memory. This issue could be caused by mis-matched BSM modules, especially if the vehicle was recently involved in an accident or work was done on the BSM system. To check if this is the issue, refer to the Repair Procedure.
SA-054-172017-08-10. Service bulletin. Blind Spot Monitoring (Advanced BSM) system frequently asked questions (FAQ)