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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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Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
SA-055-20a2020-08-05. Service bulletin. SERVICE BRAKES, AIR:SUPPLY:LOW PRESSURE WARNING:SWITCH; ENGINE AND ENGINE COOLING. If a customer comes in with the following concerns: • OIL PRESSURE WARNING light and/or the CHECK ENGINE light ON. • DTC P055F and/or P0524 stored. • No driveability concern or engine mechanical noise. • Outside the VIN range in TSB 01-020/18.
SA-054-20b2020-08-05. Service bulletin. ELECTRICAL SYSTEM; ENGINE. Some customers may experience an engine no start due to low battery voltage on 2019-2020 Mazda3 and 2020 CX-30. Inform the customer that Mazda is actively investigating this issue and apologizes for any inconvenience. Mazda would like to request both dealer and customer support to expedite a repair. Customers having this concern should be instructed to contact Mazda Roadside Assistance and have their vehicle inspected by a local dealer.
SA-029-20f2020-08-05. Service bulletin. ELECTRICAL SYSTEM; ENGINE. Some customers may experience a "IN-VEHICLE NETWORK MALFUNCTION" warning message in the instrument cluster with one or more of the following DTC's stored:
16-002-20-37222020-08-04. Service bulletin. ELECTRICAL SYSTEM; LATCHES/LOCKS/LINKAGES:DOORS:LATCH; EQUIPMENT; ENGINE. When the vehicle is in sleep mode, some customers may experience a failed remote control attempt using the MyMazda APP, however, the second attempt works fine and no DTCs are stored. Remote control functions: - Remote Engine Start/Remote Engine Stop - Remote Door Lock/Remote Door Unlock - Remote Hazard Light. This concern may be caused by improper telematics communication unit control software. To eliminate this concern, the telematics communication unit software has been modified
01-009-20-37102020-08-04. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING; EQUIPMENT. Some customers may complain about a very low frequency noise and/or vibration felt at the steering wheel, the floor and/or the seats when driving at 1500-1650 rpm in any gear position. This may be caused by normal vehicle behavior while the cylinder deactivation is active (two cylinders drive). The state of the cylinder deactivation can be monitored in the center display to help verify if this is the issue. WARNING: DO NOT keep your eyes focused solely on the display while test driving. For your safety, keep your eyes on the road ahead. To correct this concern, the radiator mount brackets and the control software of the PCM have been modified to reduce the resonance of the radiator. NOTE: The combination of the modified radiator mount brackets and older PCM calibration may result in worse vibration.
01-004-20-3684b2020-08-04. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM; POWER TRAIN:AUTOMATIC TRANSMISSION. Some customers may experience the master warning light turning on and a lack of power with DTC P2BF6:00 (Exhaust shutter valve position sensor circuit low input (1DC)) stored in memory. This is caused by improper logic written in the PCM for the exhaust shutter valve position sensor.
SA-055-202020-07-03. Service bulletin. ENGINE AND ENGINE COOLING. If a customer comes in with the following concerns, perform the inspection procedure. • OIL PRESSURE WARNING light and/or the CHECK ENGINE light ON. • DTC P055F and/or P0524 stored. • No driveability concern or engine mechanical noise. • Outside the VIN range in TSB 01-020/18.
SA-054-20a2020-07-03. Service bulletin. ENGINE AND ENGINE COOLING. Some customers may experience an engine no start due to low battery voltage on 2019-2020 Mazda3 and 2020 CX30. Inform the customer that Mazda is actively investigating this issue and apologizes for any inconvenience. Mazda would like to request both dealer and customer support to expedite a repair. Customers having this concern should be instructed to contact Mazda Roadside Assistance and have their vehicle inspected by a local dealer.
SA-054-202020-07-03. Service bulletin. ENGINE AND ENGINE COOLING. Some customers may experience an engine no start due to low battery voltage on 2019-2020 Mazda3 and 2020 CX30. Inform the customer that Mazda is actively investigating this issue and apologizes for any inconvenience. Mazda would like to request both dealer and customer support to expedite a repair. Customers having this concern should be instructed to contact Mazda Roadside Assistance and have their vehicle inspected by a local dealer.
05-002-20-37042020-07-02. Service bulletin. ENGINE; POWER TRAIN; ELECTRICAL SYSTEM:SOFTWARE. Some customers may complain about a surging at low speeds and during acceleration. This surging is in the longitudinal direction, felt about 2 cycles per second, and occurs in the locked up 1st gear. This may be caused by the torque fluctuation and the torsional resonance in the torque converter. To correct this concern, the PCM software has been modified to reduce the torque fluctuation.
01-004-20-3684a2020-07-02. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM:SOFTWARE. Some customers may experience the master warning light turning on and a lack of power with DTC P2BF6:00 (Exhaust shutter valve position sensor circuit low input (1DC)) stored in memory. The PCM software has been modified to avoid the unnecessary warning light illumination and power restriction with no modification to the cylinder deactivation function and the error detection logic has been changed not to detect false error under low voltage during cranking.
SA-048-202020-05-05. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. Some customers may expierience an engine no start condition where the engine will only start by holding the key transmitter over the Start/Stop button and DTC B13D3:97 (Remote transmitter registration work not completed) is stored. This may be caused by an accidental activation of the keyless pacemaker function.
SA-040-20a2020-05-05. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING; EQUIPMENT. Key Transmitter Power Saving Function: When the key transmitter Power Saving Function is turned ON, transmitter battery power consumption is restricted, thereby extending the transmitter battery life. IMPORTANT: • The engine will not start unless the key transmitter is held over the Start Stop button. • Outside door handle lock/unlock touch sensor is inoperative. • Key transmitter indicator lights are inoperative.The key transmitter control functions (i.e. locking/unlocking door, etc.) are operational when pressing the transmitter switches, even while the key power saving function is turned ON.
01-006-20-36952020-05-04. 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.
00-001-20-36892020-04-03. Service bulletin. SERVICE BRAKES, HYDRAULIC; POWER TRAIN; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; 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.
15-001-20-36522020-01-23. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; VEHICLE SPEED CONTROL:CRUISE CONTROL. Some customers may complain about a shift shock and/or an engine RPM increase when setting the Mazda Radar Cruise Control (MRCC) system with no DTCs being stored. NOTE: This concern only occurs on vehicles equipped with a PCM manufactured by MITSUBISHI.This is caused by improper control logic of the PCM allowing the engine RPM increase for an instant right after setting the MRCC. To correct this issue, the PCM software has been modified.
SA-053-192019-12-21. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. GUIDE LINES AND PHOTOS TO DETERMINE IF FLUID/OIL SEEPAGE OR LEAK IS SEVERE ENOUGH TO REQUIRE WARRANTY REPAIR OR TO CLEAN AND MONITOR. Some customer's might state that they notice fluid or oil leaking/dripping on the ground when the vehicle is parked. For this concern, inspect the vehicle for any trace of a fluid or oil leak and use the following examples as a guide to determine if it is severe enough to require a repair, or just to clean the area and monitor it at the next service.
MT-002-192019-12-20. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly, the replacement engine may fail prematurely. Metallic debris from the old engine (with catastrophic internal mechanical failure) may rest inside the intake manifold. When the new engine assembly is installed, debris in the intake manifold will be ingested into the new engine and cause internal damage.
01-022-19-36572019-12-20. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; 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 Bulletin is to inform you about the water pump sealing mechanism and the criteria if replacement is necessary or not.
01-021-19-36492019-12-20. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ENGINE AND ENGINE COOLING. Some customers may experience the CHECK ENGINE light ON with DTC P0012:00 (Electric variable valve timing control system: Over-retarded) stored in PCM memory. NOTE: This concern occurs only on the vehicles with PCMs manufactured by MITSUBISHI.This is caused by improper control logic of the PCM detecting a false error. To correct this issue, the PCM software has been modified. NOTE: The VVT actuator is damaged by the improper control logic.
01-020-19-36412019-12-05. Service bulletin. ENGINE AND ENGINE COOLING. Some vehicles may exhibit an excessive body vibration when idling or driving after being left in extremely cold weather (-20°F or below) for a long time. This is caused by the No.1 engine mount (1) rubber hardening due to material characteristics. NOTE: This concern only happens in extremely cold weather, therefore this TSB is only applicable for extremely cold regions.To correct this concern, the cold environment performance of the No.1 engine mount rubber has been increased by changing the rubber material.
MT-004-192019-11-24. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; ELECTRICAL SYSTEM. Some customers may complain about: • Intermittent engine no start • Instrument cluster red security indicator light ON • Engine Start/Start Button Amber indicator light flashing • Battery discharge • Electrical relay buzzing noise • DTC B13D3:94 (Communication error with remote transmitter) stored.This may be caused by: • A key in a purse near a cell phone. The cell phone radio waves may interrupt the immobilizer system. • An aftermarket cell phone charger. The charger may produce electrical noise that interrupts the immobilizer system. • An aftermarket GPS tracker. Some aftermarket devices that are wired to the vehicles’s wiring harness may create unusual electrical symptoms.
SA-044-192019-10-30. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. The "FORCED IGNITION ON PROCEDURE" was made available to dealers through this service alert.
MT-002-192019-10-04. Service bulletin. ENGINE AND ENGINE COOLING; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:MANIFOLD/HEADER/MUFFLER/TAIL PIPE. If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly, the replacement engine may fail prematurely. Metallic debris from the old engine (with catastrophic internal mechanical failure) may rest inside the intake manifold. When the new engine assembly is installed, debris in the intake manifold will be ingested into the new engine and cause internal damage.

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