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Service bulletins for the 2021 Mazda CX-3

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.

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

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Only bulletins with type: Service bulletin are shown. Show all

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SA-041-26a2026-10-03. Service bulletin. ELECTRICAL SYSTEM. DESCRIPTION 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. Examples: 1. Devices connected to the DLC-2 (battery discharge/DTC stored) 2. Devices plugged into the 12V outlet 3. GPS tracking device (engine no start/battery discharge) 4. Dash cam (DTC stored) 5. Non-certified USB cable (Apple Carplay™/ Android Auto™ will not connect) 6. Over-sized wheels/tires (incorrect GPS location) 7. DTC C0023:14 8. Decorative trim and/or cover on the START/STOP ENGINE button
01-010-262026-09-02. Service bulletin. ENGINE. This bulletin supersedes the previously issued bulletin(s) listed below. The changes are noted in Red text. 01-012/22 10/06/22 DESCRIPTION Some vehicles may exhibit accumulation of dried coolant (1) around the water pipe (2). This is caused by a gap between the housing and pipe due to a press fitting during the manufacturing process. The accumulated coolant is solidified and plugs the gap in high temperature environment and the seepage is stopped and does not progress. This is normal and does not require a part replacement, clean off the dried coolant from around the pipe with a wire brush. REPAIR PROCEDURE 1. Verify the customer concern. 2. If the above condition is experienced, remove the accumulated coolant around the pipe (1) with a wire brush etc. NOTE: Perform the procedure on the vehicle. No need to remove the water pipe and hoses.
SA-041-262026-07-03. Service bulletin. ELECTRICAL SYSTEM; ENGINE. This SA supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-061/25 12/17/25 DESCRIPTION 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. Examples: 1. Devices connected to the DLC-2 (battery discharge/DTC stored) 2. Devices plugged into the 12V outlet 3. GPS tracking device (engine no start/battery discharge) 4. Dash cam (DTC stored) 5. Non-certified USB cable (Apple Carplay™/ Android Auto™ will not connect) 6. Over-sized wheels/tires (incorrect GPS location) 7. DTC C0023:14 8. Decorative trim and/or cover on the START/STOP ENGINE button Example 1: Some electrical devices connected to the DLC-2 connector by insurance or mobile phone companies may cause: Battery discharge. The device may disrupt the CAN system battery saver mode. • IDS/MMDS will not communicate with the vehicle due to poor DLC-2 connection. The aftermarket device may cause DLC-2 female terminals to spread open.
SA-027-26a2026-07-03. Service bulletin. ELECTRICAL SYSTEM. This SA supersedes the previously issued bulletin(s) listed below. The changes are noted below in Red. SA-027/26 04/16/26 DESCRIPTION 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. NOTE: A Warranty Code is required for warranty claim submission Battery Identification (Mazda batteries have 2 rating types) 1. JIS (Japanese Industrial Standard): JIS codes are six-digit alpha-numeric markings (excluding i-STOP batteries e.g. Q-85, S-95) molded into the top of the battery to identify a battery by the capacity (amps), dimensions, and battery terminal type. Vehicles manufactured in Japan come from the factory with a JIS rated battery. NOTE: Replacement batteries may use a CCA rating. If so, use the CCA rating listed on the battery. REPAIR PROCEDURE 1. Perform appropriate repair to vehicle. If needed, use the Battery Diagnostics of the DCA-8000 to test the charging and starting systems by following the on-screen instructions for entering the appropriate information. Refer to the Mazda DCA-8000 Instruction Manual for more information.
09-019-262026-07-03. Service bulletin. ELECTRICAL SYSTEM; UNKNOWN OR OTHER; ENGINE. This bulletin supersedes the previously issued bulletin(s) listed below. The changes are noted in Red. 09-012/21 12/13/21, 06/10/21 and 04/27/21 DESCRIPTION Some customers may experience all of following symptoms: The door lock/unlock operation will not work using the remote transmitter button. 1. The door lock/unlock operation will not work using the door lock/release touch sensor. 2. The engine will not start using the ignition switch. 3. The transmitter operates by itself. 4. The key battery drains faster than usual. 5. Symptoms 1-3: This may be caused when excess load is applied to the remote transmitter, deforming the electrical terminals and creating poor contact with the battery. To eliminate this concern, the structure in the remote transmitter has been modified to reduce the deformation of the electrical terminals. Symptom 4-5: This may be caused when excessive load is applied to the remote transmitter, creating a gap around the gasket where moisture enters and corrodes the circuit board which in turn drains the key battery faster than usual. To eliminate this concern, the thickness of the case wall on the gasket mounting surface has been increased and the bonding strength of the components has been improved to prevent deformation. REPAIR PROCEDURE • If the battery is bad or installed incorrectly, replace the battery and/or install it correctly. • If the remote power saving function is off and the battery is good and installed correctly, replace the defective remote transmitter with a modified one according to the instructions on MGSS (IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING). NOTE: DO NOT replace other remote transmitter(s) for the vehicle if they not experiencing an issue.
SA-031-262026-05-05. Service bulletin. STRUCTURE:BODY; UNKNOWN OR OTHER. DESCRIPTION Some vehicles may require the replacement of a damaged VIN plate or vehicle certification label. To obtain a replacement VIN plate (bulkhead-mounted and visible through the lower-left area of the windshield), contact DAG (Dealer Assistance Group) using VIN Plate Request Form available on One Mazda. To obtain a replacement vehicle certification label (located on the B􀀀pillar or front door), contact your assigned DSM (District Service Manager) to place the order. If DSM contact information is not available, refer to the Dealer & Field Contact Directory.
SA-029-262026-05-05. Service bulletin. UNKNOWN OR OTHER; ENGINE; POWER TRAIN; SERVICE BRAKES. This Service Alert supersedes the previously issued SA listed below: The changes are noted in Red. SA-011/24 02/12/24, 06/06/24, 07/29/24 DESCRIPTION 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. SCHEDULED MAINTENANCE Refer to the applicable Workshop Manual or Owner's Manual for vehicle -specific manufacturer scheduled maintenance. Workshop Manual - Refer to section 00-00 SCHEDULED MAINTENANCE. Owner's Manual - Refer to section 8 Maintenance and Care. b. Note: Please refer to the information below outlining the services not included in Mazda's Factory Scheduled Maintenance: IMPORTANT: Recommending fluid flushes when not necessary can lead to customer confusion and dissatisfaction. Fluid flushing for preventive maintenance purposes is strongly discouraged, unless otherwise specified in a published procedure (Owner’s Manual, Workshop Manual, Technical Service Bulletin, etc.).
SA-027-262026-05-05. Service bulletin. ELECTRICAL SYSTEM. This SA supersedes the previously issued bulletin(s) listed below. The changes are noted below in Red. SA-007/25 10/22/25, 06/02/25 and 02/03/25 DESCRIPTION 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. NOTE: A Warranty Code is required for warranty claim submission Battery Identification (Mazda batteries have 2 rating types) 1. JIS (Japanese Industrial Standard): JIS codes are six-digit alpha-numeric markings (excluding i-STOP batteries e.g. Q-85, S-95) molded into the top of the battery to identify a battery by the capacity (amps), dimensions, and battery terminal type. Vehicles manufactured in Japan come from the factory with a JIS rated battery. NOTE: Replacement batteries may use a CCA rating. If so, use the CCA rating listed on the battery. 2. CCA (Cold Cranking Amps): CCA ratings are normally located on a sticker affixed to the top of the battery to indicate a battery’s Cold Cranking Amps. CCA rated batteries are supplied with domestically produced vehicles. NOTE: If an incorrect CCA rating is entered into the Mazda DCA-8000, it will result in a false result and invalid Warranty Code from the tester. This will also result in unnecessary replacement of batteries. TEST PROCEDURE 1. Connect the charger clamps to the appropriate battery posts.
SA-026-262026-05-05. Service bulletin. ENGINE. This Service Alert supersedes the previously issued M-Tip(s) listed below. The changes are noted in Red text. MT-002/19 09/30/19 and 12/19/19 DESCRIPTION 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. Clean the intake manifold internally to remove any debris from old engine before installing the new replacement engine assembly. If the intake manifold cannot be properly cleaned internally, replace it.
SA-021-262026-05-05. Service bulletin. ELECTRICAL SYSTEM; STRUCTURE:BODY. This Service Alert supersedes the previously issued SAs and bulletin(s) listed below: The changes are noted below in red. SA-010/23 02/09/23 DESCRIPTION Some customers may experience one or more electrical malfunctions after a vehicle body repair. A newly painted fender stay (2) may be causing a poor front harness (1) ground connection. The front fender stay (2) newly painted surface at ground point (3), where attachment bolt (4) is seated, may create a poor front harness ground connection. NOTE: DO NOT paint ground point (3) attachment bolt (4) is seated. NEWLY INSTALLED FRONT FENDER STAY NOTE: CAUTION: If the bolt (4) contact area (3) is painted when the front fender stay (2) is newly replaced, it could cause a malfunction in the PCM. Before painting a newly replaced part, protect the bolt (4) contact area (3) with masking tape (5) as shown in the figure.
SA-023-262026-05-04. Service bulletin. FUEL/PROPULSION SYSTEM. This Service Alert supersedes the previously issued M-Tip(s) listed below. The changes are noted in Red text. MT-003/22 03/02/22 DESCRIPTION Some customers may complain about a tapping or knocking noise coming from the rear seat after fuel fill. The concern will likely occur if the fuel tank is overfilled (more fuel is added after the fuel pump nozzle shuts off automatically) or filled up normally in high ambient temperatures and the fuel expands. No repair is needed. Explain to the customer not to continue filling after nozzle shut off.
SA-014-262026-04-02. Service bulletin. ENGINE. This Service Alert supersedes the previously issued SA(s) and TSB(s) listed below: The changes are noted in Red. SA-035/24 05/31/24 DESCRIPTION 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. A mechanical seal (A) is used for the water pump. This mechanical seal can seal coolant (B) by sliding a mating ring (C) against a seal ring (D). When the sliding surface temperature of the mechanical seal is more than 248 °F (120 °C) while driving, a small amount of steam (E) is leaked and bleeds through the bleeding hole (F). After drying, the steam leaves a green coolant deposit near the water pump bleed hole (F). This is a normal condition and does not require water pump replacement. The water pump should only be replaced if there is an accumulation of crystallized coolant near the bleed hole. When you encounter a water pump with coolant seepage marks, decide to replace it or not based on the following criteria using sample photos. NOTE: During the initial period of use*, the sliding surfaces of the seals may not yet be fully settled, which can temporarily increase the amount of leakage. Continued use will allow the surfaces to settle, reducing the leakage. Replacing parts that are already settled with new ones will increase the leakage again until the new parts become conditioned. Therefore, replacement should be avoided in this initial period of use. *As a guideline, this applies to vehicles with less than 1,860 miles (3000 km) of mileage.
01-001-26b2026-04-02. Service bulletin. ENGINE; UNKNOWN OR OTHER. Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up. Engine temperature gauge fluctuates. Low coolant temperature indicator (blue) light stays on longer or turns on while driving. Poor heater performance, especially at idle. Vehicles with SKYACTIV-G 2.5T are not applicable to this service information. DTC P0126:00 is not required to be present to perform this repair. If the vehicle has not previously had the repair specified in this TSB and is exhibiting any of the listed symptoms, proceed with the repair procedure outlined in this bulletin. If DTC P2B61:00 (Coolant Control Valve Circuit Range/Performance) is present along with DTC P0126:00, this TSB does not apply. Diagnose the symptom and/or stored DTCs according to the procedures in MGSS. If only DTC P0126:00 is present and this TSB has already been completed previously, this bulletin does not apply, diagnose the symptom and/or stored DTCs according to the procedures in MGSS. This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified. Affected vehicles will require PCM reprogramming with the Mazda Modular Diagnostic System (M-MDS), using either a) Mazda Diagnostic and Repair Software (MDARS) or b) Mazda Integrated Diagnostic System (IDS) 140.04 or later software.
SA-005-262026-02-03. Service bulletin. UNKNOWN OR OTHER. There are currently 2 methods for cutting a new auxiliary key blank. A. Auxiliary Key Trace Cut Method • B. Auxiliary Key Code Cut Method 2019 and newer models require a 10-digit key code to accurately cut keys • 5-digit codes CANNOT be provided for 2019 and newer vehicles (the traditional 5-digit code from the key tag or driver's door lock cylinder is not sufficient and will not be issued for key cutting on these models). • Only Mazda-approved key cutting machines can process these 10-digit codes. • Many older key machines do not support 10-digit codes and cannot be updated to do so. In these cases, dealers will need to purchase one of the newer Mazda-approved key cutting machines capable of handling this requirement. • For a list of current Mazda-approved machines and purchasing options, refer to the Mazda Dealer Equipment Program or view the current Mazda approved key machines below.
SA-001-262026-02-03. Service bulletin. UNKNOWN OR OTHER. Some customers may report an odor or water in the HVAC system and upon inspection, the cabin air filter may be found to be wet.
09-005-262026-02-03. Service bulletin. LANE DEPARTURE: BLIND SPOT DETECTION; ELECTRICAL SYSTEM. If the right-side Blind Spot Monitoring (BSM) control module is replaced for any reason, it is also necessary to replace the left-side BSM control module in order to complete the radar aiming procedure. If the right-side BSM control module is replaced alone, "Automatic Configuration" and "BSM Radar Aiming" cannot be completed due to a programming error in the module. In most cases, if the left-side BSM control module is replaced alone, "Automatic Configuration" and "BSM Radar Aiming" can be completed without any problem (See CAUTION below for more details). Other possible symptoms that may be found if the right-side BSM module is replaced alone: BSM aiming fails “BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54 stored in memory (CX-3, MX-5 only) NOTE: Since a new BSM control module does not retain the vehicle specification information, it is necessary to acquire and store the vehicle specification information transmitted via CAN communication from the combination meter through automatic configuration after replacement.
01-001-26a2026-02-03. Service bulletin. ENGINE. Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up. • Engine temperature gauge fluctuates. • Low coolant temperature indicator (blue) light stays on longer or turns on while driving. • Poor heater performance, especially at idle. • This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
01-001-262026-02-03. Service bulletin. ENGINE. Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up. • Engine temperature gauge fluctuates. • Low coolant temperature indicator (blue) light stays on longer or turns on while driving. • Poor heater performance, especially at idle. • This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
SA-061-252026-01-04. Service bulletin. ELECTRICAL SYSTEM. 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.
07-004-25a2026-01-03. Service bulletin. UNKNOWN OR OTHER. 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. NOTE: See parts information for Mazda Air Cooling Coil Coating and Kit part numbers.
01-003-25b2026-01-03. Service bulletin. ENGINE. Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up. • Engine temperature gauge fluctuates. • Low coolant temperature indicator (blue) light stays on longer or turns on while driving. • Poor heater performance, especially at idle. • This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
01-003-25a2026-01-03. Service bulletin. ENGINE. Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up. Engine temperature gauge fluctuates. Low coolant temperature indicator (blue) light stays on longer or turns on while driving. Poor heater performance, especially at idle. This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
SA-056-252025-12-05. Service bulletin. POWER TRAIN. When inspected, the differential or PTO oil is dark or black. This is considered normal and NO repair should be performed. During production, differential ring and pinion gears receive a manganese phosphate coating (commonly referred to as black oxide). This coating forms a porous, oil-retentive surface that improves boundary lubrication and reduces adhesive wear during initial contact cycles. Designed as a sacrificial layer, it is gradually removed under load throughout the break-in process. As a result, after the first few hundred miles, or at the initial gear oil service interval, the lubricant may appear darkened by the worn-off coating. It will contain trace ferrous particles from the normal run-in of the gear teeth and bearing surfaces. This condition is expected and does not, by itself, indicate an issue with the differential or PTO gears.
SA-055-252025-12-05. Service bulletin. SERVICE BRAKES. Some vehicles exhibit brake related concerns such as brake noise, brake judder or brake dragging. If you encounter a customer complaint for any one of these symptoms, refer to the following information to understand why symptoms may occur, and to better assist the customer in resolving their specific brake concern. NOTE: Before following this Service Alert repair procedure, ensure published TSBs in MGSS have been completed per model year.
SA-052-252025-12-05. Service bulletin. ENGINE; POWER TRAIN. 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. Examples of residue or seepage that may not be considered a leak and that may not require repair based on splash shield inspection.

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