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Service bulletins for the 2020 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.

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

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Bulletins, newest first
01-005-21-37782021-03-03. Service bulletin. ELECTRICAL SYSTEM. The Mazda DCA-8000PM is required for all warranty battery testing. If the Mazda DCA-8000PM 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-011-212021-02-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY. Section 6 of the Wireless Charging Pad instructions call for the use of an "ultrasonic cutter" to cut a rectangular hole for the harness to pass through and to serve as an access point to pop the wireless charger base out should service be required. Since an "ultrasonic cutter" is not readily available, follow the Repair Procedure to cut the rectangular hole.
SA-010-212021-02-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; LANE DEPARTURE. Some vehicles may experience M-MDS (MDARS) showing the front radar dynamic aiming is incomplete. This may be caused by: Faulty front radar sensor software logic (MDARS showing the front radar dynamic aiming is incomplete although the procedure is completed). Front radar sensor out of alignment due to vehicle accident.
SA-004-212021-02-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ELECTRICAL SYSTEM. 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: 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. TCU Activation
SA-003-212021-02-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; VEHICLE SPEED CONTROL. Some customers may complain about the following symptoms occurring when driving without anything ahead (no metallic object reflects the radar wave such as a vehicle ahead, an oncoming vehicle, a road sign or a guard rail). While using Mazda Radar Cruise Control (MRCC), the MRCC cancels by itself. When MRCC is not in use, “Safety and Driver Support Systems Temporarily Disabled. Front Radar Obscured.” message appears in the instrument cluster / “Remove dirt on the front radar sensor” message appears in the center display and related i-ACTIVSENSE functions stop working.
SA-002-212021-02-06. Service bulletin. WHEELS. Some vehicles may display incorrect tire pressures in MAZDA CONNECT and/or the MyMazda App. This may be caused by an incorrect calendar entry (month/day/year) after a battery disconnect or infotainment system software update.
SA-001-212021-02-06. Service bulletin. STRUCTURE. Refer to the Repair Procedure when installing the trunk weatherstrip for guidance, otherwise water may enter the trunk during heavy rain or when going through a car wash if it is not installed properly.
09-005-21-37622021-02-05. Service bulletin. STRUCTURE. Some customers may complain about water in the trunk compartment after a car wash or heavy rain. This may be caused by insufficient sealing performance of the trunk lid weatherstrip because the lip of the weatherstrip leans towards the inside of the trunk compartment (improper design). To correct this concern, the shape of the trunk lid weatherstrip has been modified.
09-004-21-37722021-02-05. Service bulletin. STRUCTURE. Some vehicles may experience stains appearing on the hood, roof and/or trunk of the vehicle. This concern is most likely to be found in a cold weather areas just after the RAPGARD is removed at PDI. This may be caused by moisture which has been trapped and condensed between the paint and the RAPGARD. These types of stains can be removed with a heat gun or an infrared drier.
09-003-21-37712021-02-05. Service bulletin. STRUCTURE:BODY. When encountering a vehicle with paint damage, refer to the "Mazda Paint Warranty Guide" to determine cause, prevention, remedy, and warranty coverage (if applicable).
07-001-21-37752021-02-05. Service bulletin. EQUIPMENT. A musty/mildew type odor may come from the vents when the air conditioning (A/C) system is operating. It is most noticeable when the A/C is first turned ON. This odor is the result of mold growth in the A/C evaporator/cooling unit which is caused by condensation, dust, and pollen within the cooling unit. This condition is usually worse during high humidity conditions. “Mazda Air Cooling Coil Coating” is available to encapsulate the mold to reduce odors. If the product is properly applied, it can effectively reduce the musty/mildew odor for up to three years.
02-003-21-37772021-02-05. Service bulletin. STEERING. Some customers may complain that the steering wheel is off center more than 3° even when driving straight on a flat road.
02-002-21-37692021-02-05. Service bulletin. WHEELS. Some automotive cleaning products contain strong acid or alkali. When these types of cleaners are used to clean the wheels on Mazda vehicles, the chemicals contents penetrate the clear coating of the wheel surface and damage the paint under the clear coating. The damaged area has the appearance of dark stains.
01-002-21-37672021-02-05. Service bulletin. ENGINE AND ENGINE COOLING. Some vehicle may exhibit a tapping noise from the engine during idling; etc., and synchronized to the engine rpm. The tapping noise may be caused by the switchable hydraulic lash adjuster (HLA), which may not work properly due to air bubbles accumulated in the oil passage in it.
00-001-21-37682021-02-05. Service bulletin. STEERING; WHEELS; POWER TRAIN; ENGINE AND ENGINE COOLING. 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.
SA2662021-02-01. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. MAZDA Mobile start (MMS) cannot communicate with vehicle
SA-058-20c2021-01-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM. A new cylinder head assembly for service parts has been newly established for SKYACTIV-G 2.5 with cylinder deactivation when replacement is needed. Valves, valve springs, valve spring seats, and cotters (IN/EX) are included in the new assembly. NOTE: Cylinder head replacement requires MASH authorization.
SA-035-20b2021-01-06. Service bulletin. EQUIPMENT; 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-031-20k2021-01-06. Service bulletin. ELECTRICAL SYSTEM; LATCHES/LOCKS/LINKAGES; ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY. CONNECTED VEHICLE SYMPTOM TROUBLESHOOTING: IMPORTANT NOTE: Some 2020 Mazda3 vehicles may have incorrect infotainment software version 10042 installed. The incorrect software will cause MyMazda App Connected Vehicle enrollment errors. Go to SSPC1. Some customers may complain about any of the following: · Infotainment Center Display does not provide the Authorization Code during the MyMazda App Connected Vehicle enrollment (and Software Update Error message on 2020 Mazda3 only). Remote function(s) inoperative. Engine Start / Stop · Door Lock / Unlock · Lights ON / OFF
SA-012-20e2021-01-06. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ELECTRICAL SYSTEM. 2019-2020 MAZDA3 SERVICE CAUTIONS FOR NEW AND REVISED FEATURES: Connected Vehicle, Connected Vehicle Maintenance Mode, Mazda Connected Vehicle Viewer (MCVV).
SA-004-20c2021-01-06. Service bulletin. EQUIPMENT. In order to ensure key code security, MNAO has restricted key code access for the new auxiliary key. This Service Alert provides information on how to obtain the 10-digit key code needed for cutting a new auxiliary key blank if all auxiliary keys are lost.
SA-003-20f2021-01-06. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY; STRUCTURE; ELECTRICAL SYSTEM:SOFTWARE. IMPORTANT NOTE: Some 2020 Mazda3 vehicles may have incorrect infotainment software version 10042 installed. The incorrect software will cause MyMazda App Connected Vehicle enrollment errors. Go to SSPC1. Some customers may complain about any of the following: Infotainment Center Display does not provide the Authorization Code during the MyMazda App Connected Vehicle enrollment (and Software Update Error message on 2020 Mazda3 only). Remote function(s) inoperative. Engine Start / Stop, Door Lock / Unlock, Lights ON / OFF
15-004-20-37552021-01-05. Service bulletin. ELECTRICAL SYSTEM:ADAS:BLINDSPOT:SENSORS; EQUIPMENT ADAPTIVE/MOBILITY; BACK OVER PREVENTION. Some vehicles may exhibit that both sides (right and left sides) of the Blind Spot Monitoring (BSM) and Rear Cross Traffic Alert (RCTA) system do not work
09-039-20-37472021-01-05. Service bulletin. EQUIPMENT; STRUCTURE. Some vehicles may exhibit water entering the passenger compartment from the rear door through the bottom of the service hole behind the rear door trim during rain or when washing the vehicle.
09-021-20-3714b2021-01-05. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT:ELECTRICAL:ANTENNA. Some customers may experience the master warning light and/or the "In-Vehicle Network Malfunction" warning message in the instrument cluster on with DTC B119F:01, B119F:13 and/or B119F:2B stored when the vehicle position cannot be displayed correctly.

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