Mazda CX-9 2021 — Reported problems

The contact owns a 2021 Mazda CX-9. The contact stated that while driving approximately 20 - 25 MPH, the check engine warning light illuminated. The contact used a diagnostic scanner and retrieved DTC: P0303, for a cylinder #3 misfire. The vehicle was taken to a local Mazda dealer to be diagnosed and repaired. The dealer found a coolant leak and performed a system cleaning and replaced the spark plugs and fuel injectors. However, the failure reoccurred. While the contact's wife was driving the vehicle, the check engine warning light illuminated, and the vehicle was towed to the dealer by the insurance company. The contact requested that the dealer inspect the cylinder head gasket and coolant system in his presence. The dealer informed the contact that the repair warranty would be limited to one year or 12,000 miles. The contact also contacted the manufacturer customer service but was not provided any additional assistance. The failure mileage was approximately 86,000.

2021 Mazda CX-9 (VIN: JM3TCBDY3M0538768 / 72,400 mi) Vehicle has suffered complete, sudden loss of motive power at high freeway speeds on four separate occasions. Without warning, the engine loses all propulsion, essentially stalling mid-traffic and forcing me to dangerously coast across active freeway lanes to the shoulder. This creates an extreme risk of a high-speed rear-end collision. No crash or injuries have occurred yet, but the car is entirely unsafe to drive. The authorized Mazda dealership has been completely unable to diagnose or fix this intermittent failure. Due to the persistent danger, the vehicle is currently at the shop with the same problem, where it has been since Oct 8, 2026. This is not an isolated issue. As you will see from the pictures, there are several dates where the same situation has occurred in the vehicle goes into limp mode. Mazda corporate has been contacted case 00503976. I am requesting a buyback. I request an urgent NHTSA investigation into 2021 CX-9 power loss defects for a potential recall.

I entered the interstate normally, with no issues accelerating or merging. While driving at approximately 70 mph, in traffic, all three warning messages appeared on the instrument cluster at the same time: “Smart Brake System Malfunction,” “Driver Attention Alert System Malfunction,” and “Forward Smart City Brake Support Malfunction.” At the same moment, the vehicle began to lose speed. I pressed the accelerator pedal firmly. The speed continued to decrease instead of increasing. I could not accelerate at all. An exit was thankfully immediately available. I took the exit, then continued on a side road, then into a parking lot before I could find a safe place to stop. At no point did the pedal work again — I was immensely lucky to navigate safely, especially with my toddler in back seat. Other traffic was present on the interstate at the time. The sudden loss of throttle at that speed, with traffic present on each road and merging across numerous lanes in [XXX] traffic, created a serious risk of collision while I searched for a safe stop. The vehicle has not been inspected by a dealer, it’s with Hiley Mazda of Hurst dealership in [XXX] now. TBD whether the problem can be reproduced. The vehicle can be available for inspection if needed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On a high-speed highway (Route 14), the vehicle suffered a sudden flat tire/air loss event, forcing an emergency pull-off onto a narrow shoulder with 65 mph traffic. Subsequent inspection revealed the failed tire and the rest of the set were manufactured in late 2007 (DOT code 4907). These 19-year-old tires were installed by a professional tire shop despite being far beyond their safe service life. Component/System Failed: Tires (Set of 4). Tire Size: 255/50 R20 (Vredestein Wintrac 4 Xtreme, DOT 4907). Available for inspection upon request. Safety Risk: Sudden tire failure at highway speeds created immediate loss-of-control risks and exposed occupants to high-speed semi-truck traffic on a narrow shoulder. Confirmation/Inspection: DOT date code 4907 confirmed by visual inspection. The installing tire shop was notified and acknowledged the sale/installation. Not yet inspected by manufacturer or law enforcement. Warning Signs: No warning lights, pressure drops, or symptoms occurred prior to failure. UNKNOWN if internal tread separation preceded deflation.

The vehicle was parked stationary in the driveway with the engine running for 3-5 minutes with the A/C on. The vehicle then accelerated forward into my garage causing damage. Once I entered the vehicle, both the dash and shifter displayed park. Current TCU system internal failures have been reported from the pulling of data from Mazda.

1) What component or system failed or malfunctioned: On 6/12/2026 While drive on the highway with our daughter in the car and we experienced a high speed stall. The engine failed and we lost power. We barely got the car of the highway and coasted into a parking lot. 2) Life threating for Father, Mother and daughter and other drivers on the highway. 3) The Mazda dealer stated they were unable to reproduced problem. The diagnostic report showed few random misfired on two cylinders 2 & 3. Autozone detected codes P0300 with Secondary DTCs U0442-00 4) There car was only inspected by the dealer. The vehicle has not been inspected by Mazda the manufacturer. We requested Mazda to escalate this to the District Service Manger and to open hotline call with Mazda corporate but both of these were denied. All our service has been performed at Mazda dealer, including oil changes. We have always received a video of them working on our car with a detailed summary of what done. We did not receive the video or diagnostic report for this issue. 5) There were no warning lamps, no messages or other symptoms of the problem prior to the failure.

This complaint refers to Mazda and it's dealer refusal to properly execute the warranty work under the SSPD5 Valve Stem Seal Class Action Campaign and does not follow the Court's approval of the final Settlement Agreement. I assert that Mazda and it's dealer are not following the SSPD5 repair procedures. 1. I have documentation and complaints going back to Dec-2023 with this particular dealer that I have experienced low level oil consumption within the 7,500 mile oil change interval. The dealer did not detect oil leaks in any of the engine systems. 2. I presented the vehicle to the dealer with the Engine Oil Level Warning Light illuminated. The Diagnostic Trouble Code (DTC) P250FF:00 should be stored in the vehicle memory. 3. The vehicle had 50,501 miles and was within the original 60 month limited powertrain warranty. 4. The dealer refused to conduct the valve stem seal repairs until an oil consumption test was run. The dealer claims that because I had another service center (note that I use full synthettic oil that meets Mazda oil specifications) conduct the most recent oil change at 43,738 miles (note within the 7,500 oil change interval and the 1 year time window) that the dealer would require an oil consumption test. I assert that this is not required per the class settlement agreement and the SSPD5 repair procedures that Mazda sends to all of its dealers. 5. I researched the available documentation that it's available through the NHTSA.gov. The language in these documents is very clear. 6. SSPD5 Valve Stem Class Action Campaign, Repair Procedure 6-12-2024: a. "The DTC250 is not required to be present for valve stem replacement." b. "Customer complaint of oil consumption...OR Low Oil Light OR DTC250 follow the flow chart." c. Flow chart says "Replace the exhaust valve stem seals by following TSB 01-003/24" if no previous warranty work done. 7. SSPD5 updates on 8-6-25 and 4-28-26: a. Refer to page 4, DTC250 is NOT required to be presented (it is noted in RED).

Check engine light comes on and error P0303 comes on. Had an independent mechanic do the following and after each one, error P0303 still came on 1. Swap the ignition coils from 2 to 3 2. Swap spark plugs from 2 to 3 3. Swapped injectors 4. Compression test 5. Leak down test 6. Changed the spark plug, coil and injectors 7. Looked for vacuum leaks. Mechanic believes that it is related to the cracked cylinder head in the recall, MC-10232269-0001.pdf. My vehicle is just outside of the recall range and has 87k miles on it. Other research online shows other people with the same vehicle and similar milealge are also having this problem.

Backup camera shows three to four feet before red collision line is not accurate causing severe damage to my garage door.

My vehicle is part of Mazda's 2021-2022 Mazda Valve Stem Seal Settlement. The dealership had yet to call me in for the repair of said valve seal repair as I was on a list. The settlement is suppose to extend out the powertrain warranty on the vehicle 2 years/24,000 to 7 years/84,000. My vehicle has 60,083 miles on it. One of the cylinders on my vehicle lost compression. The dealership and Mazda both say they will not cover the cost for repair as they only are covering things in the powertrain relate to oil consumption. The cylinders are part of the powertrain and carbon buildup from excessive oil burning because of the defective seal causes valve damage or sticking which will cause compression loss. Mazda is actively denying what they agreed to in the settlement and costing people money for repairs that should be covered.

My MazdaCx9 engine consumes (burns) an excessive amount of oil, necessitating frequent top-offs between oil changes.This issue started after the first oil change and continued since then.

On [XXX], [XXX], [XXX] I was driving on an interstate highway with a 65 mph speed limit with no warning and received the following codes which slowed the vehicle to the limp mode. 1) Smart Brake Support and Forward Obstruction Warning 2) Activsense system malfunction 3) Front Radar Sensor Malfunction 4) Engine Malfunction 5) Dynamic Stability Control Malfunction I reported all three incidents to the dealer and no codes were left and the dealership had no solution for the problem. They suggested dirt, sunlight, or blowing debris caused it, but that was not the case. Luckily the first two incidents happened with little or no traffic around but the third was during rush hour and almost caused a major accident trying to get off the highway. I shut the car off, restarted and the problem resolved no lights left on or warnings appearing all three times. Contacted Mazda several times and all representatives at the dealership and California Headquarters claim no knowledge of this happening. I found a few others reporting the same issue and wanted to report this. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Hello, I have been to a Mazda dealer complaining of clicking and squeaky brakes for 2 years now. Dealer replaced both front and back breaks and rotors around 22k year ago and to my surprise the issues persist, currently vehicle is at 49k. There is a TSB( 04-001/22) out for my vin and year, so they know its a manufacturing defect and all they do is throw white break grease and a month later the noise is there again when breaking , backing up. I am not the only one, people of reddit confirm this and so does a general google search. Besides that i love the car and the dealer was super cool about it all but I'm sorry, this is unacceptable, Every time i go get an oil change i ask about a fix and nothing.

Please add the 2021 CX9 model to the following bulletin. [XXX] This is exactly what is happening with my car and is extremely frustrating that a recall has not been issued to fix the problem. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 Mazda CX-9. The contact stated while driving at various speeds and turning, there was a popping sound coming from the front end of the vehicle. The front-end popping sound also occurred while driving over bumps in the roadway. The vehicle was taken to an independent mechanic who was unable to determine the cause of the failure. The vehicle was not repaired. The local dealer and manufacturer were not notified of the failure. The failure mileage was 68,811.

Car loses oil and coolant rapidly

The contact owns a 2021 Mazda CX-9. The contact stated that while accelerating quickly and entering the highway, there was no motive power to the vehicle. While crossing the highway in the right lane, driving at 65 MPH, the vehicle in front moved over; there was a parked vehicle. The contact was able to stop the vehicle before causing a crash. The driver was starting to accelerate, but there was no motive power when the accelerator pedal was depressed. The smart brake system malfunction message was displayed. There were no warning lights illuminated. The contact called the local dealer, who scheduled an appointment. The vehicle was not diagnosed or repaired. The manufacturer was contacted and informed the contact to have the vehicle diagnosed. The failure mileage was approximately 53,186.

Consumes over 2 quarts of oil between recommended oil changes. The dealer made excuses about needing to use a different oil but it has not improved the problem. The warning light for low oil went off after less than 3000 miles. It was 2 quarts down.

I was leaving for work when I put my personal items in the front passenger side first and then continued to walk around the car to get to the drivers side. Once I closed the passenger side door the car auto locked with all of my items in it including the key. Thankfully I had my cell phone in my pocket which has access to open the car via the Mazda app but it would not work. The spare key was not at the current location the car was at. We had to call someone out to unlock the car. This poses a safety problem because if I put my child in the back seat and close the door to get to the drivers side and it auto locks with them inside as well as my key I would have to resort to breaking the window to get them out. I reported this to Mazda and they deny that it’s a problem, and I have had the vehicle inspected by Mazda and they claim nothing is wrong with it and reset the computer. No warning prior to this happening and my key has never been locked inside before. The battery in the key is not old or dead.

I just purchased this vehicle 2 months ago. Yesterday my oil light came on, I pulled over and checked the oil it was completely low. I had to put a quart of oil in it. After that I did some research and learned this seems to be an issue with some 2021 models the cx9 included. There needs to be a recall on this and Mazda needs to fix this issue. These cars cost way to much to have to put a quart of oil every month.

I was in a parking lot and came to a stop and placed the car in reverse to back into a parking space. The back-up camera was on and I began to back into the parking space when the car suddenly lurched/jerked forward and accelerated on its own. The car jumped the parking lot median strip and I hit a tree head on. I had my seatbelt on and the airbag deployed. The car then reversed back off the median into the parking lot. I turned off the car. Insurance company will have it inspected. The vehicle is a total loss. I was injured with a large lower abdomen hematoma and airbag burns on arms, wrists, and chest as well as various bruising. I was fortunate to have not hit pedestrians who were walking in the lot or other vehicles that were parked in the lot. There were no warning lights, messages, sounds. The brake assist did not engage. It was frightening.

6/29/2023--Vehicle stopped suddenly with i-ACTIVESENSE system malfunction, Dynamic Stability Control malfunction, Engine malfunction, engine output reduced, Front radar sensor malfunction. Dealer said these faults due to bad battery--replaced battery per Service Manager [XXX] at Lakeland Mazda. 9/10/2023--Incident #2 with same faults as above with vehicle stopping suddenly at risk of creating a rear end collision. Lakeland Service Manager [XXX] now said that the faults are due to a faulty ERG valve. Lakeland Mazda and [XXX] are absolutely clueless as to the root cause of this problem and are releasing the vehicle back to the customer with the potential of causing a significant collision that can result in serious injury and/or death. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I was driving approximately 75-80 mph (speed limit for I-90 is 80 mph) on I-90 Eastbound in South Dakota (approximately 5-8 miles from Sioux Falls, SD) in the left-hand lane (passing lane with a minimal shoulder) when I heard a terrible noise that sounded like I had a flat tire and the car began to pull to the left. I immediately slowed down and steered the vehicle onto the small shoulder on the left-hand side of the interstate. It was at this point I looked out my window (driver's window) and saw the entire left front wheel (not just the rubber tire) rolling by (west in the grassy median of I-90). The vehicle did not roll over, hit another vehicle, or get hit by another vehicle. After coming to a safe stop, I got out of the vehicle and saw that the left front (driver's side) wheel (not just the rubber tire) was gone. There were two (2) other passengers in the vehicle at the time that the wheel fell off who exited the vehicle out of danger of passing cars/trucks/semi tractor trailers on I-90. The vehicle was towed and to my knowledge has not been inspected by the manufacturer. The Hertz rental vehicle was only "inspected" by PurCo claims specialist via pictures as they did not have the vehicle in their possession. There were no warning messages, lamps, lights, or other symptoms prior to the wheel falling off. The wheel fell off on 7/8/2023 on Interstate 90 in South Dakota. After the wheel fell off, it rolled down the median of I-90 bounced up onto the westbound lane of I-90 and struck another vehicle causing that vehicle's airbags to deploy. There were four (4) occupants in that vehicle.

The oil light keeps coming on before your initial oil change. Also, the oil is actually low. They have already changed it and I'm having the same problem in less than 2 months.

2021 Mazda CX-9 Frontal collision at a speed between 10-20 mph. Car shut down after collision and was not drivable. Concern is the driver side airbag did not deploy. (Neither did passenger but there was no person in the passenger seat)

Oil light came on, vehicle has ~15,000 miles.

the vehicles experience excessive oil consumption because the defective valve stem seals allow engine oil to leak into the combustion chambers. This concern usually occurs when the mileage reaches approximately 2,000 – 3,000 miles (5,000 - 7,500km) and may also occur again after replacing or topping off the engine oil.

2021 Mazda CX-9 Low Oil Light came on at around 18,900 miles (2/10/2023 and 2/11/2023). Took to Mazda, and they said there was defective valve stem seals that can allow oil to leak into the engine’s combustion chamber. Vehicle is currently with Mazda service department to be fixed.

The contact owns a 2021 Mazda CX-9. The contact stated that while driving at 60 MPH or exceeding 60 MPH, the vehicle would lose motive power and stall without warning. The contact stated that he would coast to the side of the road and the vehicle would restart after 2-3 attempts and regain normal functionality. The vehicle had not been diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 49,000.

The driver side airbag did not deploy in a front end collision on the drivers side. When approaching a vehicle that had come to a sudden and complete stop, the brakes were applied hard to the Mazda CX-9 in order to stop, but after about 1 second they just totally let go and there was no braking at all and the Mazda continued to move forward until it slammed into the vehicle that was stopped. The MyMazda app sent a message that stated that there was a Brake System Malfunctiom which is exactly what occurred and caused the accident.

A LOT OF ENGINE OIL CONSUPTION, 1 QUART PER 2500 MILES.

My 2021 Mazda CX-9 uses excessive engine oil as reported in the Mazda "M-Tip" bulletin MT-005/20 and this manufacturer's defect is reportedly caused by defective valve stem seals as claimed in the class action lawsuit U.S. District Court for the Central District of California, Southern Division: [XXX] v. Mazda Motor of America, Inc. The valve stem seal problems allegedly cause excessive oil consumption between regular oil change intervals, which increases the risk of engine damage and failure. I believe Mazda must address this issue as soon as possible and repair my affected vehicle before I suffer catastrophic engine failure or long-term engine damage. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

1000 miles before first ever oil change was needed (according to window sticker provided by Mazda) the low engine oil light came on. The oil was low and needed to be toped off and brought directly to dealer for oil change. The same thing happened again 1300 miles before second oil change was required. It became obvious that the brand new vehicle was burning oil for some reason. The dealership tried to tell us that it was because the car was a turbo. We weren’t buying it and told them we wanted it looked at. After brining it into the dealer they mentioned that Mazda had a bulletin for a valve seal fix that might help it stop burning oil. So they admitted that yes it was burning oil. After googling the bulletin I realized that our vehicle is having the same problems that many others with 2021 Mazdas (certain production period) are having. There is currently no recall however there is proof that these problems are damaging our vehicle, putting my wife and children at risk every time they get in the car and Mazda is doing nothing about it. There is also proof that these gases from the burnt oil are damaging other engine systems further increasing the likelihood of an engine failure. Down the road. Chances are this damage is already done, despite this valve seal repair.

REAR PASSENGER HANDLE AND HOOK ABOVE SEAT IN ROOF SPLINTERED INTO SHARP PROJECTILES FLYING THROUGH CABIN WHEN AIR BAG DEPLOPYED I SHOWED THE SHARP PIECES TO MY INSURANCE ADJUSTER THE POWER OF THE RIGHT CURTAIN AIR BAG DEPLOYMENT BROKE THE HANDLE TO PIECES AND IF ANYONE HAD BEEN IN THE BACK SEAT THEY COULD HAVE HAD AN EYE PUT OUT OR BEEN EMPLAILED BY THE SHARP PIECES

Massive oil consumption. Uses 1 quart or more of engine oil at around 3,000 miles after oil change. Low oil light comes on...

The low engine oil light is coming on every 3500 miles. When checking oil level it indeed is low and requires a quart of oil. There is an active TSB out as this is a known issue but no recall issued yet.

New Mazda vehicle engine is consuming approximately 1 quart of oil, approximately every 3,500 miles. No recall for this yet, however Mazda technical service bulletin TSB # 01-012/21 admits this is a common and known issue for this vehicle which may eventually lead to the vehicles engine and parts no longer functioning.

Every 4,000 miles my engine oil warming light comes. When the dealership checked my oil level, it was about a quart low.

I purchased this vehicle June 5 2021. The vehicle has approximately 9150 miles at this time. I changed the oil the first time at 3222 miles just because it was new and I wanted to have a starting point on oil changes. The car has an app you load on your cell phone for messages. The first time I received a massage that the engine was low of oil was around 6700 miles. I checked it and it was low with at the add oil mark with 3500 miles driven. I received a second message from the app stating the oil was low. Again, I checked the oil and it was to the add oil level with 9014 miles or only been driven 2300 miles. I have contacted Mazda and will take it to the dealership in a few days, but I am having to add and check the oil ever day or so. There seems to be an oil consumption issue with this engine.

On 4/30/2022 the rear door lift gate opened unexpectedly and hit the ceiling of a parking garage (The Summit at Las Calinas, Irving Texas) , the glass window shattered, glass fell in and outside the car. An unfamiliar beeping was heard before the accident, but the source could not be located prior to the impact with the ceiling. A lift gate ajar warning indicator light likely flashed on the dash but was not noticed. We surmised that the root cause was likely due to unintentional pressing of the rear lift gate key fob button (driver had put key fob in pants pocket). This unintentional and unexpected opening of the lift gate has happened on at least 4 prior occasions when the key fob lift gate button has been unintentional pressed. One time resulting in being hit in the head with the lift gate! Potential Risks: 1) People near the rear of the car can be struck when the lift gate unexpectedly opens, 2) Young children who are sitting in the third seat are exposed, 3) Trunk contents can spill out if not secured, 4) Valuables are exposed if lift gate opens while parked unbeknownst to the driver, 5) Damage to vehicle if rear lift gate opens in a home garage and hits the garage door, 6) other Mazda owners as reported on Reddit.(https://www.reddit.com/r/MazdaCX9/comments/mf3h5w/back_trunk_opening_by_itself/) Problem was reported to TOWN NORTH MAZDA dealer. Insurance claim not filed because cost of window replacement is below deductible. We were grateful that no one was hurt and that the car could be driven home.

AS I WAS DRIVING DOWNHILL WITH MINIMAL SNOW ON THE GROUND, I TAPPED MY BRAKES ABOUT 7 TIMES BEFORE THEY LOCKED UP. I WENT TO TURN TO STAY ON THE ROAD AND THE STEERING WHEEL WOULDN'T BUDGE CAUSING ME TO GO OFF THE ROAD, INTO AN EMBANKMENT. VEHICLE WAS GOING ABOUT 5-10MPH WHEN THIS OCCURED ON A CITY STREET.