WenmarOpen by Wenmar Pro

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.

By type

By component

By trouble code

By topic

Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
SA-031-21c2022-01-05. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. New Cylinder Head Assembly Established: 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.
01-012-21-3832a2021-12-02. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. Some vehicles may have a “LOW ENGINE OIL LEVEL” warning message and a CHECK ENGINE light illuminated in the instrument cluster, along with DTC P250F:00 stored in memory. DTC P250F:00 - Engine oil level signal: engine oil level low. Upon inspecting the engine oil level, the level is found to be low and there doesn’t appear to be any trace of oil leakage in the engine compartment. This concern usually occurs when the mileage reaches approximately 3,100 – 4,700 miles (5,000 - 7,500km) and may also occur again after replacing or topping off the engine oil. The root cause of this concern has not been identified yet, therefore a repair procedure will be announced at a later date. Since this issue has been reported after a valve stem seal modification, it is very likely that valve stem seal damage is causing oil to leak into the combustion chamber.
SA-031-21c2021-11-01. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. 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. Dealers can now utilize the Limited Parts Ordering (LPO) page on eMDCS to order the repair parts for 2.5L (with cylinder deactivation) and 2.5L turbo cylinder head repairs. There is no longer a need to contact hotline for part ordering. If there are any questions on part ordering or part status, contact the DAG group for assistance.
SA-031-21b2021-11-01. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN; EQUIPMENT. 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.
01-012-21-38322021-10-31. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; ENGINE AND ENGINE COOLING; TIRES:VALVE. Some vehicles may have a LOW ENGINE OIL LEVEL warning message and a CHECK ENGINE light illuminated in the instrument cluster, along with DTC P250F:00 stored in memory. DTC P250F:00 - Engine oil level signal: engine oil level low. Upon inspecting the engine oil level, the level is found to be low and there doesn't appear to be any trace of oil leakage in the engine compartment. This concern usually occurs when the mileage reaches approximately 3,100 - 4,700 miles (5,000 - 7,500km) and may also occur again after replacing or topping off the engine oil. The root cause of this concern has not been identified yet, therefore a repair procedure will be announced at a later date. Since this issue has been reported after a valve stem seal modification, it is very likely that valve stem seal damage is causing oil to leak into the combustion chamber.
SA-047-212021-10-05. Service bulletin. ENGINE AND ENGINE COOLING. If you receive a customer concern about the CHECK ENGINE light coming on and DTC P3400 (cylinder deactivation system malfunction) stored, the cylinder deactivation oil control valve may be plugged with plastic debris from the oil filter wrapper. The debris may enter the center of the oil filter when poking a hole in the filter wrapper during removal, and then travel through the engine and plug the cylinder deactivation oil control valve.
MT-002-212021-10-02. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. Ethanol is becoming a common additive in gasoline. Gasoline containing ethanol is likely available at your local gasoline station. Typical blends of ethanol include E10 and E85. E10: A blend of 10% ethanol and 90% gasoline, E85: A blend of 85% ethanol and 15% gasoline, All Mazda vehicles can run on gasoline containing up to 10% ethanol (E10) but only some 1999-2001 B3000 trucks can run on gasoline with more than 10% ethanol blended. E10 compatible vehicles: All Mazda vehicles. E85 compatible vehicles: 1999-2001 B3000 Mazda trucks with the 8th VIN digit is V. What if a customer puts E85 in there Mazda vehicle? Symptoms include: Rough Running, Lean Codes, Misfires and/or misfire codes, Lack of power, Poor fuel economy, Spark knock, Mechanical engine damage.
01-011-21-3800a2021-10-02. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; 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. NOTE: Vehicles with SKYACTIV-G 2.5T are not applicable. Due to production variety of the failsafe thermostat integrated in the coolant control valve, engine coolant may enter into a dry hollow in the failsafe thermostat, resulting in unintended opening of the failsafe thermostat at lower temperatures (104-176 °F (40-80 °C)). To eliminate this concern, the production process of the coolant control valve has been modified.
SSPC72021-09-03. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM:12V/24V/48V BATTERY; COMMUNICATION:MANUFACTURER TELEMATICS. SSPC7 - SPECIAL SERVICE PROGRAM -TELEMATICS COMMUNICATION UNIT BATTERY DRAIN CONCERN AND CONNECTED SERVICES NOT AVAILABLE
SA-031-21a2021-09-03. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST 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.
SA-045-21d2021-09-03. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY; EQUIPMENT:ELECTRICAL; ENGINE. Connected vehicle remote functions inoperative and/or engine no start due to low battery voltage. NOTE: SA-045/21 HAS BEEN SUPERCEDED TO SSPC7.
SA-045-21c2021-09-03. Service bulletin. EQUIPMENT:ELECTRICAL; ELECTRICAL SYSTEM:12V/24V/48V BATTERY; ENGINE. Connected vehicle remote functions inoperative and/or engine no start due to low battery voltage. Some customers may experience the following symptoms: Connected Vehicle Remote Functions inoperative after SSPC6 repair. Connected Vehicle Remote Functions inoperative on vehicles built March 20, 2021 and later.
SA-045-21b2021-09-03. Service bulletin. EQUIPMENT:ELECTRICAL; ENGINE; ELECTRICAL SYSTEM:12V/24V/48V BATTERY. Connected vehicle remote functions inoperative and/or engine no start due to low battery voltage. Some customers may experience the following symptoms: Connected Vehicle Remote Functions inoperative after SSPC6 repair. Connected Vehicle Remote Functions inoperative on vehicles built July 1, 2021 and later.
SA-045-21a2021-09-03. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY; ENGINE; EQUIPMENT:ELECTRICAL. Connected vehicle remote functions inoperative and/or engine no start due to low battery voltage. Some customers may experience the following symptoms: Connected Vehicle Remote Functions inoperative after SSPC6 repair. Connected Vehicle Remote Functions inoperative on vehicles built July 1, 2021 and later.
01-006-21-3779a2021-09-03. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY; ENGINE AND ENGINE COOLING. This service bulletin provides testing and charging procedures in order to promote proper battery maintenance, to deliver new vehicles with fully charged batteries, and to reduce unnecessary battery replacement cost. For new vehicles in stock at the dealer, inspect and maintain the battery periodically according to the repair procedure.
SA-013-21f2021-07-02. Service bulletin. ENGINE AND ENGINE COOLING; EXTERIOR LIGHTING; EQUIPMENT ADAPTIVE/MOBILITY. 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, MAZDA CONNECT connected vehicle reception strength icon shows "X" or " ".
SA-012-21f2021-07-02. Service bulletin. ENGINE AND ENGINE COOLING; SERVICE BRAKES. MAZDA CONNECTED SERVICES - FREQUENTLY ASKED QUESTIONS (FAQ): Index: General Questions, Setup and Getting Started, Registration / Enrollment, WI-FI General Information, WI-FI How-To, WI-FI Trial Period, Interacting With The App, Service Issues, Troubleshooting, Reception Level Inspection, Dealer Processes, Conditions for Remote Engine Start Will Not Function, Conditions for Remote Engine Start Function Will turn engine OFF, Educational Videos, Resources
SA-012-21e2021-06-03. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY. MAZDA CONNECTED SERVICES - FREQUENTLY ASKED QUESTIONS (FAQ): Index: General Questions, Setup and Getting Started, Registration / Enrollment, WI-FI General Information, WI-FI How-To, WI-FI Trial Period, Interacting With The App, Service Issues, Troubleshooting, Reception Level Inspection, Dealer Processes, Conditions for Remote Engine Start Will Not Function, Conditions for Remote Engine Start Function Will turn engine OFF, Educational Videos, Resources
SA-013-21e2021-06-03. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY; EXTERIOR LIGHTING. 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, MAZDA CONNECT connected vehicle reception strength icon shows "X" or " ".
SA-038-212021-06-02. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING. When the body control module (BCM) has been replaced or reprogrammed and the software is updated to the file names shown below, DTC U2050:55-BCM (Activation of remote control not implemented) may be stored in memory without any warning indication for the driver.
MT-002-212021-06-01. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. When programming a key or installing a Genuine Mazda Accessory Remote Engine Start system, you may encounter programming difficulty. This may be caused by a customer installed aftermarket decorative trim and/or cover on the START/STOP ENGINE button. The aftermarket accessory may create electrical interference, which may interfere with programming.
MT-001-212021-06-01. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING; EQUIPMENT. 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 Workshop Manual diagnosis. Aftermarket devices may be the cause of the electrical concern. Ask the customer if any aftermarket devices have been installed.
01-004-21-3773a2021-05-04. Service bulletin. ENGINE AND ENGINE COOLING. Some vehicles may have the check engine light on with DTC P0524:00 or P055F:00 stored in memory. Contamination in the engine oil may cause the engine oil solenoid valve to become stuck, resulting in improper operation of the oil pump and improper oil pressure. DTC P0524:00 (Engine oil pressure too low), DTC P055F:00 (Engine oil pressure malfunction). The control software of the PCM has been modified to eliminate this concern. In addition, the production process has been modified to reduce contamination in the engine oil solenoid valve, oil pump, spacer and oil filter.
01-002-21-3767a2021-05-04. 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. To eliminate this concern, the switchable HLA has been modified for increased oil supply to reduce air bubbles in the oil passage. NOTE: The switchable HLA can be pressed down with a finger if air bubbles have accumulated in it.
SA-012-21c2021-04-06. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY. MAZDA CONNECTED SERVICES - FREQUENTLY ASKED QUESTIONS (FAQ): Index: General Questions, Setup and Getting Started, Registration / Enrollment, WI-FI General Information, WI-FI How-To, WI-FI Trial Period, Interacting With The App, Service Issues, Troubleshooting, Reception Level Inspection, Dealer Processes, Conditions for Remote Engine Start Will Not Function, Conditions for Remote Engine Start Function Will turn engine OFF, Educational Videos, Resources

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