2021 Mazda Mazda3

My rear differential case cracked, anytime the four wheel drive system was engaged the entire drivetrain would lock up. Luckily we were only on side roads so going less than 30 mph if we had been on the highway when this happened we could have been in an accident or lost control. The dealer did confirm the problem and it was fixed under an extended warranty. There was no warning just all of a sudden a loud bang and all the wheels locked up. I have a copy of the video inspection done at the dealer if there's anyway to send that. I can get a copy of the repair invoice if needed

NHTSA ID

11713224

Incident

Feb 2, 2025

At 31,000 miles the control arm lower ball joints are torn on both lower. They must be replaced. This is a safety hazard. This should not be an issue with low mileage on this car.

NHTSA ID

11695896

Incident

Oct 25, 2025

I was driving when all the sudden there was a loud bang sound. The differential housing cracked. The when awd is demanded the rear diff was was locking up instead of engaging. Luckily we were just on city streets and not on the highway as this rear wheel locking up could cause a crash. Mazda wasn't very helpful with the replacement. Luckily I had a aftermarket warranty but it only paid for a used replacement, which is also failing. I have read lots of stories of this rear differential failure across all types of Mazda's from this era and really wish they would do the correct thing and resolve the problem.

NHTSA ID

11663288

Incident

Jan 31, 2025

Spontaneous loss of power while driving on highway. Check engine light came on. Speed limited by car. Continues to vibrate especially at idle from cold start. Code P0304 intermittently popping up.

NHTSA ID

11656416

Incident

Apr 21, 2025

During the incident, the vehicle exhibited an uncontrollable malfunction—the steering wheel suddenly jerked sharply to the right while accelerating violently, leaving me unable to steer or brake effectively, the car was looking forward. The car ultimately came to a stop upon colliding with a truck parked diagonally in front of me. After impact, I observed that the front tires remained stuck in a turned-right position, with the steering wheel also locked in that position. This was not an isolated event. Multiple reports from Mazda owners describe similar experiences with their vehicles unexpectedly veering to the right and accelerating without driver input. Given these recurring reports and my own experience, I strongly suspect that a manufacturing defect—whether mechanical, electronic, or software-related—may have contributed to this accident.

NHTSA ID

11645615

Incident

Feb 5, 2025

The driver window, upon attempted to be let up, will start to go up then go all the way down, ignoring the function to go up. This is a safety concern, as harsh temperatures and foreign objects are able to enter the vehicle cabin at any time, including driving. The problem has been reproduced by a dealer, and the vehicle is available for inspection upon request. There are no warning indicators for this issue beyond witness the failure occur in real time.

NHTSA ID

11644043

Incident

Mar 13, 2024

When this feature is left on in my vehicle, it will detect curves, vehicles, and objects that are not there, and as a result, will attempt to turn my steering wheel (safety concern). I have had to keep this feature turned off to prevent it wrecking the car, because I could be on a straight road, and it will detect a curve that isn’t there and begin turning the wheel, which could result in a fatal accident if not corrected and disabled by the driver. It is available for inspection upon request. As the dealer has not driven the vehicle, they have not recreated the error, however if anyone were to drive the vehicle, they would be able to observe the malfunction. The dealer has been made aware on many occasions, though they never documented it and only suggested that I turn the feature off, which automatically turns itself on upon ignition. There are no warnings that there is a malfunction; you only know there is an error once an alert pops up thinking you’re missing a curve and attempts to turn your steering wheel though there is no curve. This issue has persisted over the life of the vehicle.

NHTSA ID

11644042

Incident

Jan 26, 2021

The thermostat malfunctioned on this vehicle, resulting in the thermostat remaining open and providing excess coolant to the engine, which in turn damaged internal components of the engine (compromises safety), decreased fuel economy, increased emissions (compromised safety), and decreased the life of the engine within the vehicle. It is available for inspection upon request. The vehicle has been inspected by an independent mechanic and will be inspected by the Mazda dealership in 7 days. There were no prior warnings until the engine malfunction notice appeared, the vehicle began to make jolts and stuttering sounds, and the temperature gauge within the vehicle failed to rise to optimal range. As this occurred while the vehicle was in use (safety concern), though I was pushing the gas there would be delayed response due to improper temperature, which increased the risk for an accident to occur.

NHTSA ID

11644041

Incident

Feb 14, 2025

DESCRIPTION Some customers may complain that the electric power steering warning light illuminates after engine start and DTC U2011:1C is stored. Zinc-plated whisker may form inside the EPS motor and trigger the DTC. However, since it is cleared when power is supplied during DTC detection, normal operation can be restored by turning the ignition OFF and then ON. Furthermore, there is no possibility of recurrence. This case may be resolved through a simple inspection or repair without the need for parts replacement, potentially avoiding unnecessary customer waiting time.

This SA supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-063/24 09/06/24 DESCRIPTION The Blind Spot Monitoring (BSM) system can malfunction with the following symptoms if the rear side radar sensors are installed facing the wrong direction.

This bulletin supersedes the previously issued bulletin(s) listed below. The changes are noted in Red. 09-016/26 05/06/26 DESCRIPTION Some customers may complain that the seat warmer does not operate when turning the ignition on while the seat is warm but when turning the ignition off then on again, the seat warmer begins to operate appropriately. DTCs “B1030:13” and/or “B1032:13” are stored. This is caused by the seat warmers fail-safe mode which prevents it from working during the initial drive cycle. To correct this issue, the seat warmer has been modified to optimize the temperature control. B1030:13 Seat warmer unit (LH) circuit malfunction (Heater side) B1032:13 Seat warmer unit (RH) circuit malfunction (Heater side) Customers having this concern should have their vehicle repaired using the following repair procedure. REPAIR PROCEDURE 1. Verify the customer concern. 2. Remove the front seat cushion trim and the front seat back trim for both the driver and passenger seats according to the instructions in MGSS.

This Service Alert supersedes the previously issued SAs listed below. The changes are noted in Red text. SA-017/25 12/16/25, 09/08/25, 07/14/25, 05/15/25 and 03/21/25 DESCRIPTION Mazda Connect Frequently Asked Questions (FAQ) Index General Questions MAZDA CONNECT Indication Setup and Getting Started Dealer Processes Registration / Enrollment / Take-Over Customer Subscription Status WI-FI General Informatio Opening the TCU Communication Line WI-FI How-To Conditions for Remote Engine Start Will Not Function WI-FI Trial Period Conditions for Remote Engine Start Function Will turn engine OFF Interacting With The App TCU Communication Line Status Service Issues Educational Videos Troubleshooting Resources MyMazda App Error Codes Customer Opt-Out

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.

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.