2021 Mazda Mazda3 Complaints

POWER TRAIN — Filed 02/02/2025

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

SUSPENSION — Filed 10/25/2025

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.

POWER TRAIN — Filed 01/31/2025

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.

ENGINE — Filed 04/21/2025

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.

STEERING,ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL — Filed 02/05/2025

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.

ENGINE — Filed 02/14/2025

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.

FORWARD COLLISION AVOIDANCE,LANE DEPARTURE — Filed 01/26/2021

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.

ELECTRICAL SYSTEM,UNKNOWN OR OTHER — Filed 03/13/2024

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.

ENGINE — Filed 12/16/2024

The contact owns a 2021 Mazda Mazda3. The contact received notification of an unknown Class Action Lawsuit Number however, the part to do the repair was unavailable. The contact stated that the manufacturer exceeded a reasonable amount of time for the repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.

POWER TRAIN — Filed 11/26/2024

Radiators are failing 3 years after the warranty period. Its leading to coolant lost and perhaps overheating the engine.