2021 MAZDA Mazda3 Problems

Complaints Reported

Complaints by Component

ENGINE

16 complaints

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.

Apr 23, 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.

Feb 21, 2025

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.

Dec 16, 2024

Low oil light - car is burning oil and only has 11,400 miles. Approx 3/4 to 1 quart missing...

Sep 21, 2024

Driving on a remote highway in northern WI and low oil light illuminated, 1000 miles before oil change was due with less than 10k miles on the vehicle. Made it to a gas station and oil was a quart low. Vehicle burns over a quart every oil change interval, since this has been occurring since day 1 it is likely going to cause premature engine failure which would be a safety issue.

Jun 19, 2024

+ 11 more complaints for this component

UNKNOWN OR OTHER

4 complaints

My 2021 Mazda 3 was bought used in August 2023 and is about a year old in my possession. it has been at the Mazda dealership for repairs multiple times since August 2023. it dangerously stalls and hesitates when trying to accelerate from a stop position. When the brake pedal is released and I start to accelerate like merging onto highways,the car rumbles or shakes slightly and then shuts off. I Came across a review online that had the exact same problem and it stated a PCM update solved the issue. I have been to the dealer frequently since purchased and they kept my car for over a week and claimed they could not reproduce the customers complaint and there is no diagnostic code generated. There is Frequent parking light malfunction alerts, switch operation not accepted alerts, Brake alerts on desolate roadways I believe this vehicle behavior is dangerous on multiple levels, but the dealer Refused to remedy the complaint or give me copies of the papers that I signed, stating they are only for the dealership. I also received a notice in the mail for a class action settlement for faulty fuel pump used in MAZDA vehicles but not the 2021 Mazda 3 although it displays the same Dangerous behavior. So between the faulty fuel pump or required PCM update the vehicle is questionable to drive safely under certain circumstances. The dealer inferred I should have purchased a used certified Mazda from them instead. Thanks

Nov 20, 2024

While driving at a normal speed on a clear, sunny day with no other vehicles close by, I heard a loud crash sound and my car's sunroof unexpectedly shattered. The inside glass panel looks like it's shattered and it caused tiny glass shards to fall inside the vehicle onto my right arm and the surrounding area. I closed the cover to prevent more from falling. This occurred without any prior warning, signs, or symptoms such as unusual noises or warning lights from the car. This incident posed a significant safety risk, not only due to the distraction, shock of the sudden noise, glass falling, injury in a potential accident, but also the potential for physical harm from the glass shards. Thankfully, no injuries occurred, but the potential for serious harm was evident. This problem has not yet been inspected by the dealer or confirmed by an independent service center, and there has been no opportunity for an inspection by any manufacturer, police, or insurance representatives. However, I've reached out to Mazda, both locally and corporate and am receiving a run-around, no surprise. I will attach photos of the inside and the outside of the glass. The outside photo was taken after the cover was closed. However, the broken sunroof is available for inspection upon request.

Jun 21, 2024

Part easily break away during washing. Fuel door cover lid panel (BDYT-42-411) broke in automatic car wash.

Dec 30, 2023

A have a new 2021 Mazda 3 Hatchback with 3,500 miles. As I was driving and approaching a traffic light to stop, my car shut down completely while in traffic. I turned on my hazard lights, put the car in the park position, and restarted the vehicle. As I proceed with driving, when I made a right turn onto the blvd, a minute after turning when I came to another stop, the vehicle shut down again. I called Romano Mazda in Syracuse, NY. They set me up with an appointment for the following week and gave me a rental. They kept my vehicle for 3 days. Per the technician, there were no codes found or pending codes. said they contacted the Mazda tech line and was told there was no history of the fault within the ODR date and released my vehicle back to me. My vehicle only has 3,500 miles on it. ITs a huge safety hazard. I transport my mother who is 93 years of age. I don't feel confident driving it. especially on the highways. In 2019 over 262,000 Mazdas, including the Mazda 3 hatchback were recalled for problems with vehicles stalling out. Sound like the same issue with the 2021's

Apr 10, 2022

AIR BAGS

4 complaints

Air bag malfunction light comes on a and goes off multiple times while driving

Sep 04, 2022

The vehicle was badly rear ended and the airbags didn't deploy. The dashboard indicated an "airbag malfunction" after the collision happened. The failure of the airbags put myself and my passengers at serious risk; if we weren't wearing our seatbelts, which we were, we would have been gravely injured. The vehicle is less than a year old and still under warranty.

Jun 11, 2022

Crash: 1

Injuries: 1

My car started to show a warning on the dashboard that the airbag system is malfunctioning. The alarm would come on for a few seconds, then turn off, then repeat like that multiple times every drive. At the time it started, my car had less than 500 miles on it, and it continued after that until I got it fixed. I took it to the Mazda dealership where I bought it, and they said it was a short circuit to the driver's side airbags. They told me that could have caused the airbags to deploy prematurely or not at all in an accident. I am also a part of a Mazda 3 community and am active on the forums, and in the last month I have seen at least 30-40 other 2021 Mazda 3 owners also report the same exact error code, with the same short circuit issue being cited as the problem by the dealership. Parts are on backorder for weeks for most of these owners, and some of them were told by the dealership to keep their car while they waited for the part, whereas my own dealership told me it was unsafe to drive the car and to have it towed to the dealership instead.

Apr 08, 2022

Instrument panel display shows a warrning message: Air Bag System Malfunction. Have the Vehicle inspected.

Dec 18, 2021

FORWARD COLLISION AVOIDANCE

3 complaints

At red light, close behind car in front of the mazda. After light turns green, start driving the mazda after car in front moves forward. Although the car in front is moving forward at a higher rate of speed, increasing the distance between it and the mazda, the automatic emergency brake kicks on and stops the vehicle abruptly. Luckily the cars behind the mazda reacted in time and did not rear end it.

Sep 11, 2024

Vehicle detects cars in other lane as an impeding collision in turns, activates emergency braking when no collision is imminent.

Aug 08, 2022

2021 MAZDA 3. CONSUMER WRITES REGARDING FAILED SBS SYSTEM. *LD THE CONSUMER STATED THE SMART BRAKE SYSTEM SLAMS ON THE BRAKES UNNECESSARILY, WHILE DRIVING. THE CONSUMER WAS ADVISED BY THE DEALER THAT FEATURE COULD NOT BE DISABLED. *JS

Apr 15, 2021

POWER TRAIN

2 complaints

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.

May 27, 2025

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

Nov 26, 2024

SERVICE BRAKES,FORWARD COLLISION AVOIDANCE

2 complaints

During a night drive, travelling approx. 40mph, car warning system audio blared a warning and suddenly braked causing car to skid (was raining) and causing driver to also jolt forward with momentum. There was very little time between beginning of audio warning and car slamming on brakes.

Jan 31, 2023

I had two incidents during a short 25 min drive. Incident 1: I was in right side of the road, there were 2 lanes on this side. I was in the far left lane driving at below 30 mph, there was no vehicle directly behind me, and no vehicle directly in front of me. There was no vehicle in the oncoming side of traffic. There was 1 vehicle in the right lane next to me, about 20 feet behind. This vehicle slowed down to turn right into a parking lot. I did not have my foot on the brake at all, the vehicle behind me was in no way veering into my lane or doing anything abnormal. At this point, all of a sudden my car hard braked automatically. I had not touched the brake and I was driving straight and not veering. It was very sudden, and very hard braking, and it jerked me in my seat because of how hard the brake had suddenly turned on. Incident 2: After that first incident, there was a second time when this happened on the same trip. Once again, this time I was driving at about 35 mph. It was again where there were two lanes on my side of the road and I was in the left lane. No vehicles were in front or behind me. In the right lane next me to, there was 3 vehicles in a row about 25 feet behind me, and the front vehicle of them stopped to turn right into another parking lot area. The same thing happened, I did not have my foot on the brake at all, and had not veered at all and was driving straight. The brakes automatically came on suddenly in a very hard brake, resulting again in a sudden complete stop, even though there were no cars in directly in front or behind me. The vehicle was brought brand new at the dealership , so I had no cause to have the brakes inspected by the dealership, police, or insurance company. There was a warning that the safety features had been disabled due to obstruction of the front sensor, but there was no warning lamps that the emergency automatic brake was going to be used, it just happened.

Jan 09, 2022

ELECTRICAL SYSTEM

2 complaints

The contact owns a 2021 Mazda Mazda3. The contact stated that while driving at various speeds the passenger front side tire was flat which caused the contact to veer to the shoulder. The contact towed the vehicle to the dealer where the tire was inspected as the technician informed the contact that the tire was on backorder and no replacement tire was available. The vehicle then was towed back to the contact resident however was informed by the towing company that the vehicle abrupted in flames on the flatbed. The fire department was contacted and extinguished the flames. No police report was made. no injuries were sustained. The contact is awaiting approval from the insurance adjustor on adjustments needed to be made for the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximate 2,509.

Sep 07, 2021

Fire: 1

TL* THE CONTACT OWNS A 2021 MAZDA MAZDA3. THE CONTACT STATED WHILE THE VEHICLE WAS AT A STAND STILL AT A PARKING LOT, WHEN IT CAUGHT FIRE. THE FIRE DEPARTMENT WAS ABLE TO EXTINGUISHED THE FIRE AND FILED A REPORT. THE POLICE WAS AT THE LOCATION BUT DID NOT FILE A REPORT. THE VEHICLE WAS DRIVABLE BUT WAS TOWED AT A TOW LOT. THE CONTACT CALLED LOCAL DEALER MORONG FALMOUTH MAZDA (187 US-1 #1311, FALMOUTH, ME 04105: (207) 781-4020) AND WAS MADE AWARE OF THE FAILURE. THE VEHICLE HAD NOT BEEN DIAGNOSED OR REPAIRED. THE MANUFACTURER HAD BEEN INFORMED OF THE FAILURE. THE FAILURE MILEAGE WAS APPROXIMATELY 1,500.*DT*JB

Mar 16, 2021

Fire: 1

SUSPENSION

1 complaint

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.

Oct 27, 2025

STEERING,ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL

1 complaint

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.

Feb 28, 2025

Crash: 1

FORWARD COLLISION AVOIDANCE,LANE DEPARTURE

1 complaint

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.

Feb 21, 2025

ELECTRICAL SYSTEM,UNKNOWN OR OTHER

1 complaint

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.

Feb 21, 2025

SERVICE BRAKES

1 complaint

Brakes are underpowered especially when hot. Drove 20-30 minutes in traffic and when decelerating from 60 mph highway in turn lane to turn into neighborhood the brakes felt very soft . Car only has 28k miles on it and pads have plenty of life left. Have seen similar complaints on online forums.

Jun 19, 2024

WHEELS,UNKNOWN OR OTHER

1 complaint

For the past 7 months (since July 2023) the passenger rear tire keeps loosing air pressure about every two weeks requiring more air. It always drops to 10 points below the other tires. The tires have been rotated twice so it is not a problem with the tire. I believe there is a recall for the same or similar issue on Mazda 3s just not including my VIN#. I brought my car to good year a few times unable to stop this from happening.

Feb 20, 2024

STRUCTURE

1 complaint

A bolt head underneath the car snapped for the steering mechanism. The problem was indicated by a clanking noise I heard for many 1000s of miles. It's been as long as I remember, but I had no idea what it really meant. It's 2.7 years old with 30,653 miles right now. There were no warnings. The wheel could have come off at any moment I was driving it. The bolt was likely over-torqued or had a manufacturing defect causing it to snap. I have pictures for when the car was propped up at a technician. One side is completely non rusted. The other side is showing rust ONLY from where the bolt was covering, so rust is an unlikely cause.

Feb 15, 2024

UNKNOWN OR OTHER,ENGINE

1 complaint

Experiencing a known excessive oil consumption issue. Low engine oil warning light came on and upon checking, oil was low. This occured at 4000 to 4200 miles. It occured again about 4000 miles later and again at a similar interval. I notified the dealer and scheduled a repair date but I am concerned of other possible damage that may have already occured due to this issue. An oxygen sensor needs to be replaced and is most likely due to the engine malfunction. The cause of the consumption is said to be damage to the valve seals on the exhaust side.

Apr 02, 2023

SEAT BELTS

1 complaint

The latches inside the driver's seatbelt receptacle feel like they wear out over time. The only reason I can tell is because there is a really noticeable creaking that develops from inside the receptacle while the seatbelt is connected. This is worse for drivers with bigger waists and as the driver's waist continues to tug on the seatbelt during operation, the creaking gets worse over time. There are no electronic warnings. The seatbelt still properly connects and there are no electronic messages saying that anything is wrong with the seatbelt. My driver's original seatbelt receptacle has already been replaced once under warranty at a Mazda dealership. Now the second seatbelt receptacle is starting to do the same thing again after about 6 months of use. I fear that even if I get it replaced a second time, this will just continue to happen. Perhaps there is a manufacturing defect. As this issue continues to get worse, I fear that this creaking will develop into a major failure with the seatbelt connection itself.

Jan 06, 2023

STRUCTURE,ENGINE,FUEL/PROPULSION SYSTEM

1 complaint

Car emits a very audible squeak when shifting right above 30mph and 40mph, car surges at lower and constant speeds, tach will slowly drop when applying throttle, surge slightly, then function as normal again

Jan 02, 2023

SERVICE BRAKES,FUEL/PROPULSION SYSTEM

1 complaint

Strong unburnt fuel smell had just started at 6700 miles. Mazda Dealership stated that they would not be looking at my car and that gas smells are normal... After this encounter, I had 2 mechanics look at my car. Both had concluded that the smell predominantly comes from near the rear driver wheel, under the body, and that it is an extremely dangerous situation. I am a full time student and do not feel safe driving this car to class but I have no choice since Mazda is neglecting this issue. I also reported to the dealer that my brakes seem to be defective since they are causing excessive shaking when applied. Dealer informed me that they do not warranty the OEM brakes that came on my car, however Mazda Corporate informed me that they do. I do not feel safe driving this car knowing the car may combust and harm me and others on the road. The brakes also do not inspire confidence. A complaint has been filed with Mazda Corporate.

Sep 25, 2022

WHEELS

1 complaint

This new car has less than 8000 miles on it and suddenly 3 of 4 BRIDGESTONE TIRES Turanza el440 215/45R18 89 have sidewall bubbles. Interesting that there are a ton of issues w sidewall Bridgestone tires on line yet the dealership keeps claiming the car must have been run over a median? Without any damage anywhere on the car? Come on.. it is clearly a manufacturer defect. They have history with sidewall bubbling. Consumers getting shafted at best and maimed at worst. Do something please!

Aug 15, 2022

ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL

1 complaint

Context: ADAS was not on. Lane keep assist is disabled in system settings entirely as it is dangerous. Blinkers were on, I was pulling out from parallel parking into left turn lane onto a straight road with slight incline. Car is of the Turbo trim on stock tires. Upon finishing pulling out of parallel parking spot and gassing the car, torque vectoring or some underlying collision avoidance may have phantom activated. I felt torque shift to the wrong tires, unsettling the car, and the wheel -- with no human input -- jerked to the left to force me into the lane left of intended. I applied throttle and steered right back into the correct lane, but the car was applying torque to the wrong tires and applying a left bias to the steering. Only after I got above 25mph and held straight did the car settle. Almost caused an accident if the lane was not empty due to car unsettling itself into the left lane.

Jan 22, 2022

LANE DEPARTURE,FORWARD COLLISION AVOIDANCE

1 complaint

The error code "B14FO-76 FORWARD SENSING CAMERA DEVIATION - WRONG MOUNTING POSITION" was discovered, and verified, by a Safelite Auto Glass service center when the 2021 Mazda 3 was in for a repair (stone chip) to the windshield on September 21, 2021. There were no warning messages nor lights to alert the driver as to the improper installation/mounting of this device. There has been no known modification to nor obstruction of the FSC -- its condition is now as it was received new from the dealer. Improper mounting ("Wrong Mounting Position") of the Forward Sensing Camera affects multiple safety systems of this vehicle, which affects the safety of the vehicle's passengers as well as everyone's safety around the vehicle every time it is driven -- there's no telling what injury and damage may occur from an errant un-commanded driving tasks such as emergency braking and faulty lane departure corrections.

Sep 28, 2021

ELECTRICAL SYSTEM,LANE DEPARTURE

1 complaint

PASSENGER SIDE BLIND SPOT WARNING FUNCTIONS SPORADICALLY. IT SOMETIMES DETECTS VEHICLES AND SOMETIMES DOES NOT WHILE DRIVING AT THE SAME SPEED.

Feb 14, 2021

⭐

4.3/5.0

94 reviews

Frequently Asked Questions

How many problems does the 2021 MAZDA Mazda3 have?

The 2021 MAZDA Mazda3 currently has 48 owner-reported complaints according to NHTSA database. These complaints are organized by component to help identify common issues.

What are the most common problems with 2021 MAZDA Mazda3?

The most common problems reported for the 2021 MAZDA Mazda3 are organized by component above. Each component section shows owner-reported issues, crash reports, and fire incidents to help identify patterns and problem areas.

Where does this 2021 MAZDA Mazda3 problem data come from?

All problem and complaint data for the 2021 MAZDA Mazda3 comes directly from the National Highway Traffic Safety Administration (NHTSA) database. These are real complaints submitted by actual vehicle owners.