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Service bulletins for the 2021 Mazda Mazda3

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.

634 on file from NHTSA, as of 2026-10-19.

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Bulletins, newest first
SA-009-24a2024-03-06. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Frequently Asked Questions (FAQ): General Questions, Reception Level Inspection, Setup and Getting Started, Dealer Processes, Registration / Enrollment, TCU Activation, WI-FI General Information, Conditions for Remote Engine Start Will Not Function, WI-FI How-To Conditions for Remote Engine Start Function Will turn engine OFF, WI-FI Trial Period, Deactivation Mode, Interacting With The App, Educational Videos, Service Issues, Resources, Troubleshooting Page.
SA-009-242024-03-06. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Frequently Asked Questions (FAQ): General Questions, Reception Level Inspection, Setup and Getting Started, Dealer Processes, Registration / Enrollment, TCU Activation, WI-FI General Information, Conditions for Remote Engine Start Will Not Function, WI-FI How-To Conditions for Remote Engine Start Function Will turn engine OFF, WI-FI Trial Period, Deactivation Mode, Interacting With The App, Educational Videos, Service Issues, Resources, Troubleshooting Page.
SA-011-242024-03-06. Service bulletin. STEERING; SERVICE BRAKES, HYDRAULIC; WHEELS; TIRES; ENGINE AND ENGINE COOLING; POWER TRAIN. Mazda has developed factory recommended scheduled maintenance services that support all major vehicle systems. Mazda recommends dealers follow the scheduled maintenance tables as cited in the vehicle-specific workshop manual or owner's manual. Services performed outside of Mazda's factory scheduled maintenance are not recommended. These services are unnecessary and create unneeded expenses for your customers.
SA-006-242024-03-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ELECTRICAL SYSTEM. Customers having MAZDA CONNECT concerns should have their vehicle repaired using the following repair procedure.
SA-007-242024-03-06. Service bulletin. SERVICE BRAKES, HYDRAULIC. NOTE: Before proceeding, perform MGSS Vehicle Inquiry (MGSS -> Other Applications -> Warranty Veh. Inq. -> RECALLS / SPECIAL SERVICE PROGRAMS -> Status) and check for Open campaigns. If any of the following campaigns are open, complete the campaign before proceeding with this service information. SSPC5 - 2019-2021 MAZDA3 AND 2020-2021 CX-30 - CONTROL UNITS REPROGRAMMING 4219L - 2019MY MAZDA3 SUDDEN DECELERATION FROM FALSE BRAKE ACTIVATION 2024 CX-90 with VINS lower than JM2KK******151673 (produced before November 25, 2023), VCM software update available using TSB 15-001/24. DESCRIPTION This information will give you the necessary knowledge to respond to customers concerns of Smart Brake Support (SBS) unintended braking. By educating the customer on the system operation, it should reduce their anxiety or distrust of the vehicle. IMPORTANT: Humans recognize an object with their eyes and decide whether or not to apply the brakes using their brain. The vehicle recognizes objects using the Forward Sensing Camera (FSC) and Front Radar sensor (FR), to determine brake application. Therefore, drivers may feel that the operation does not match the human feeling.
09-001-24a2024-03-06. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. Some customers may experience a “Telematics Malfunction” message in the instrument cluster with DTC U3000:04-TCU (Telematics communication unit internal malfunction) stored in memory. This is caused by improper control software of the telematics communication unit (TCU). To eliminate this concern, the control software of the TCU has been modified.
09-001-23a2024-01-06. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Some vehicles may exhibit an “In Vehicle Network Malfunction” message appearing in the instrument cluster with DTC U3000:04-TCU (Telematics communication unit internal malfunction) stored after the connected service contract has been discontinued. This is caused by improper control software of the telematics communication unit (TCU). To eliminate this concern, the control software of the TCU has been modified
01-005-23a2024-01-06. Service bulletin. ENGINE AND ENGINE COOLING. Some customers may experience the check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: The engine takes longer to warm up The engine temperature gauge fluctuates The low coolant temperature indicator (blue) light stays on longer or comes on while driving Poor heater performance, especially at idle
SA-081-232024-01-06. Service bulletin. ENGINE AND ENGINE COOLING. There is a concern that some water pumps are being replaced that are not faulty, due to signs of a very small coolant leak from the bleed hole. This Service Alert is to inform you about the water pump sealing mechanism and the criteria if replacement is necessary or not.
SA-025-23a2024-01-06. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY. When the Telematics Control Unit (TCU) replacement is necessary due to a failure, use MDARS to activate the new TCU after replacement. Use the information in this service alert to initialize the new TCU until the procedure on MGSS is updated.. CAUTION: DO NOT swap TCU with another vehicle as the TCU is VIN locked after activation. A TCU swap with another vehicle will disable Connected Services on both vehicles. If TCU activation is not performed, connected vehicle functions will not operate. This will have a negative impact on the customer because they will need to return to the dealer for repairs.
SA-021-23b2024-01-06. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT:ELECTRICAL:WIRELESS CHARGER/CRADLE. Qi Wireless Charger symptom troubleshooting
SA-015-23e2024-01-06. Service bulletin. EQUIPMENT:ELECTRICAL; ELECTRICAL SYSTEM. Frequently Asked Questions (FAQ): General Questions Reception Level Inspection Setup and Getting Started Dealer Processes Registration / Enrollment TCU Activation WI-FI General Informatio Conditions for Remote Engine Start Will Not Function WI-FI How-To Conditions for Remote Engine Start Function Will turn engine OFF WI-FI Trial Period Deactivation Mode Interacting With The App Educational Videos Service Issues Resources Troubleshooting Page
SA-079-232024-01-05. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; VISIBILITY. Some customers may complain about color discrepancies (brightness differences) of the image displayed on the screen when using the 360°view monitor. As this phenomenon is not a system failure, do not make any repairs or replace any parts.
SA-077-232023-12-05. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; SERVICE BRAKES, HYDRAULIC. This information will give you the necessary knowledge to respond to customers concerns of Smart Brake Support (SBS) unintended braking. By educating the customer on the system operation, it should reduce their anxiety or distrust of the vehicle.
SA-027-23c2023-12-05. Service bulletin. ELECTRICAL SYSTEM; UNKNOWN OR OTHER; EQUIPMENT ADAPTIVE/MOBILITY. In-Vehicle Network Malfunction error message and Master Warning light ON with DTC U3000:04 (Telematics communication unit internal malfunction) stored.
09-040-232023-12-05. Service bulletin. FUEL SYSTEM, GASOLINE. When opening the fuel-filler lid to refuel, some customers may notice water and/or sand in the fuel-filler lid box area. They may complain about dried sand causing poor appearance.
09-039-232023-12-05. Service bulletin. EQUIPMENT:ELECTRICAL:INFOTAINMENT; ELECTRICAL SYSTEM; EQUIPMENT:ELECTRICAL:INFOTAINMENT:SOFTWARE. Some customers may experience no sound from the audio system and/or the audio source cannot be changed. This concern may be caused by the remote tuner not operating properly under certain situations. To eliminate this concern, the remote tuner control software has been modified.
09-038-232023-12-05. Service bulletin. SUSPENSION:REAR:SPRINGS:AIR SUSPENSION SYSTEM; UNKNOWN OR OTHER. Some customers may complain about the poor appearance due to an uneven rear beltline molding joint. This concern is caused by the rear beltline molding not being manufactured according to the original designed shape. To eliminate this concern, the rear beltline molding manufacturing process was improved to prevent form shape discrepancies from the original design.
09-029-23a2023-12-05. Service bulletin. LATCHES/LOCKS/LINKAGES; UNKNOWN OR OTHER; ELECTRICAL SYSTEM. Some customers may experience one or both of the following symptoms while locking and unlocking the doors works fine using the remote transmitter. Symptom 1: The touch sensor of the front door outer handle does not lock the doors after rain and/or car washing, even though unlocking is possible. Symptom 2: The touch sensor of the front door outer handle does not unlock the doors.
09-007-23c2023-12-05. Service bulletin. SEATS. At PDI or when new vehicle is delivered, some customers may complain about wrinkles on the leather seat cushion and/or seat back surface.
05-005-23a2023-12-05. Service bulletin. POWER TRAIN. Some vehicles may exhibit a chirp noise (stick-slip noise) from the automatic transaxle (AT) when shifting from 3 to 4 while driving. This may be caused by the automatic transaxle fluid (ATF) being contaminated by iron powder due to excessive wearing of the lock up clutch in the torque converter.
01-007-23a2023-12-05. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. The Mazda DCA-8000 is required for all warranty battery testing. If the Mazda DCA-8000 is not used, incorrect battery testing may result in unnecessary battery replacement. Use the following test procedures in this Service Bulletin to test Mazda vehicle batteries and to generate a Warranty Code.
SA-032-23a2023-11-02. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY. If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s) stored...), interview the customer before proceeding with normal MGSS diagnosis by asking if any aftermarket devices have been installed. Aftermarket devices may be the cause of the electrical concern. Below are a few examples of unusual electrical concerns caused by aftermarket devices.
05-005-232023-11-01. Service bulletin. POWER TRAIN. Some vehicles may exhibit a chirp noise (stick-slip noise) from the automatic transaxle (AT) when shifting from 3 to 4 while driving. This may be caused by the automatic transaxle fluid (ATF) being contaminated by iron powder due to excessive wearing of the lock up clutch in the torque converter.
01-010-23a2023-11-01. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ENGINE AND ENGINE COOLING. Some customers may complain about engine surging 100-200 rpm when accelerating up a hill at altitudes around 6,700 feet or higher. This concern may be caused by improper PCM control software in particular situations. To eliminate this concern, the PCM control software has been modified.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.