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 the federal safety agency investigation into 2021 CX-9 power loss defects for a potential recall.
Mazda CX-9 loss of power problems
39 of the 1,496 owner complaints about the Mazda CX-9 describe sudden loss of power, most of them for the 2010 model year.
- owner complaints
- 39
- worst model year
- 2010
- typical repair cost reported
- $5,000
- typical mileage
- 84,564
By model year
Often reported together
Engine failure 12Overheating 11Check engine light 9Stalling 7Power steering loss 3Won't start 2Won't shift 2Misfire 2
Trouble codes mentioned
P0016 2U0442 1P064A 1P0300 1P0192 1
What owners say
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.
The cylinder head on this 2018 Mazda CX-9 (Skyactiv-G 2.5T engine) cracked, allowing engine coolant to leak and intermix with engine oil, causing loss of coolant and catastrophic engine failure. The vehicle became undriveable in the first week of November 2025 at approximately 125,019 miles and has remained inoperable since; it was not in a crash and had to be towed. This matches a known, documented defect on Mazda's Skyactiv-G 2.5T engine: coolant leakage at the cylinder head near the exhaust manifold, leading to overheating and engine failure. Mazda issued technical service bulletin(s) addressing cylinder-head cracking and coolant intrusion, revised the cylinder-head casting (a superseding part number), and extended warranty coverage (program CSP11) for this specific concern. This vehicle fell just past the mileage cap of that extension. Safety risk: a cracked cylinder head causing coolant loss and engine overheating can produce sudden loss of engine power and overheating if it occurs while driving. No crash, fire, or injury resulted in this case. A formal dealer diagnosis is pending; the failed engine/cylinder head is being preserved and is available for inspection on request.
The engine cylinder head developed an internal coolant leak, allowing coolant to enter the combustion chamber. This caused engine overheating and smoke coming from the tailpipe while driving. A dealer performed a coolant pressure test confirming coolant leaking into the combustion chamber, and wet/dry compression testing on all 4 cylinders showed low and inconsistent readings consistent with cylinder head coolant intrusion (Cylinder 1: 105/125 psi, Cylinder 2: 115/125 psi, Cylinder 3: 110/175 psi, Cylinder 4: 160/190 psi). Overheating creates a risk of sudden loss of power and potential engine failure while driving, including on the highway. The problem has been confirmed and diagnosed by an authorized dealer service center, and the manufacturer's technical hotline department reviewed the diagnostic findings directly. Warning symptoms (overheating codes and visible tailpipe smoke) first appeared at the time the vehicle was brought in for diagnosis. The manufacturer has an active technical service bulletin addressing cylinder head coolant leaks on this engine and model, along with a related warranty extension program, but has denied coverage for this repair on the basis that the leak is internal rather than external.
My 2019 Mazda CX-9 (VIN [XXX]) suffered catastrophic cylinder head failure on the SKYACTIV-G 2.5T engine at approximately 124,000 miles. The failure is consistent with Mazda TSB 01-013/21 (and successors 01-007/22, 01-010/24), in which Mazda acknowledged that cylinder heads on this engine can crack at the stud bolt hole and exhaust manifold flange due to manifold deformation and residual production stress. The first warning came in mid-May 2026, when the engine temperature warning illuminated during normal driving. An independent mechanic replaced the thermostat. The warning returned within a week, and the thermostat was replaced a second time with a higher-quality part. Four to five days later, the warning returned alongside more severe symptoms: the vehicle began jerking while in motion, a strong coolant-burning smell developed, and smoke was visible from the exhaust pipe upon shutdown. The vehicle became undriveable, had to be left at the failure location, and was towed. Safety risk: The jerking compromised vehicle control in traffic. Upon shutdown, smoke and burning coolant odor created fire and fume-exposure risks. Had this failure occurred at highway speeds or in heavy traffic, the sudden loss of engine power and erratic behavior could have caused a serious collision. Family members were in the vehicle during several escalating events. Confirmation: The vehicle was towed to an authorized Mazda dealership, where Mazda-certified technicians confirmed in writing that it is exhibiting the exact defect described in TSB 01-013/21 and that complete engine replacement is required. The diagnosis is formally documented and has been communicated to Mazda's warranty team. Mazda Customer Experience has been engaged since mid-May 2026 and acknowledged the issue. The vehicle is currently at the dealership and available for inspection upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Engine running rough. Check Engine Light illumination. Difficulty starting or a no-start condition. Noticeable loss of power during acceleration Check engine light P0192
I was driving the vehicle on the highway when the vehicle started to overheat, lights started blinking, the car was smoking, losing power and acceleration. This car has a recall on the cyclindwr head which when cracks causing the car to loose coolant and oil. If it cracks while you’re driving especially on the highway the car will immediately loose coolant and oil thus causing a very dangerous driving condition. There was no indicator prior to the failure that there was anything wrong with the car. No check engine lights, no coolant lights nothing. Prior to this happening I smelled coolant in the car cabin , took it to my mechanic who tested the coolant system and found no leak. At the time he was unaware of the known issue these cars have with the cylinder head. The problem has been confirmed by Mazda and they notified me within the month of March of the problem and the extended warranty to replace the known manufacturer defect cylinder head. The Mazda dealer now has my car and acknowledges the cracked cylinder head caused the problem but said because I didn’t immediately stop on the highway and kept driving until I got to a safe location I was negligent and are refusing to fix the car which now has a blown engine, etc. it is available for inspection now at the Mazda dealer. My safety was put at risk because I could have died on the highway if the car completely stopped working, it was dangerous driving it when it first started happening because it started out of nowhere the car was fine I was driving 50+ mph and it started smoking, overheating etc. I could have also killed someone else. It is a disgrace that not only they won’t fix my car they want to say they won’t because I’m negligent? I drive my kids to and from school everyday do you think I’m going to risk their safety in an unsafe car? They should not only fix the car but compensate me for putting mine and my children’s lives at risk. A complete disgrace.
While driving on an interstate service drive in Michigan, my 2018 Mazda CX9 GT suddenly lost power and began flashing overheating warnings. I tried to move my vehicle to a safe spot while the warning and sudden loss of power was happening, which took a moment due to traffic flow and my family being in the car. I moved the car off the road, and let it cool. I slowly drove the car to a parts store to get coolant. Once the cooling system was filled, I brought the car home and began researching the problem. According to internet threads like Reddit this is a wide spread problem happening among Mazda vehicles with several law firms researching class action lawsuits. My car is stuck at the dealership until I can find $12,000 to fix it, and sadly there are hundreds more just like me according to sites like [XXX] and [XXX] [XXX] [XXX] [XXX] [XXX] [XXX] And includes a Mazda Service Bulletin which indicates that there are design faults in the original cylinder head that causes the issue and that repair techs should replace failed parts with the updated and redesigned cylinder head. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
1. What component or system failed or malfunctioned, and is it available for inspection upon request? The entire electrical system is malfunctioning. All dashboard service lights (check engine, ABS, etc.) illuminate simultaneously, causing the vehicle to stutter and shut off while driving. The vehicle is available for inspection. 2. How was your safety or the safety of others put at risk? This issue has resulted in a dangerous situation, particularly when the vehicle lost power on the highway with my young children aboard. This sudden loss of control could have led to a severe accident. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Mazda’s service department has not been able to reproduce the problem despite multiple visits. I have provided video evidence, but no conclusive diagnosis or resolution has been achieved. 4. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? Mazda’s authorized technicians have inspected the vehicle several times, but no substantial action has been taken. The vehicle has not been inspected by police or insurance representatives. 5. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? All dashboard lights come on simultaneously without prior warning. The symptoms have been random and intermittent over the past few months. Given the ongoing risk, I request an immediate replacement of my vehicle. Please confirm receipt of this complaint and provide a plan for replacement. Thank you for your prompt attention.
This is the second time my car mazda -2017 had problem with fuel pump. I only saw recall for 2019 Mazda CX-9 in internet. Before the fuel pump fail, I smelled gas inside the car which I was told my mechanic later from the shop where I bought my car for immediate diagnose was considered dangerous. The first time happened 2 years ago when we were on the trip 250 miles from where we live. This time we were about 200 miles away. So the fuel pump it seemed became the problem for Mazda. When we asked Mazda about it they said it is not the same with recall for 2019. If those car has the problem with fuel pump and got the recall why Mazda 2017 did not get recalled? They said it is wear and tear but it is the same issue fuel pump. we spend $912 for original part and bought it from Mazda dealer but we couldn’t get reimbursed because they said it is not a recall. I am filing this complaint because they denied the problem with Mazda is actually and consistently fuel pump!. I have kids that I have to bring to school. Smelling gas, the car stop suddenly and lost power will get us into accident. So I am writing this to let you all know that 2017 Mazda has the same problem with 2019 Mazda which is fuel pump. Please take this seriously. Thank you
Related recalls
No recalls on record for this model year.
Questions about the Mazda CX-9 loss of power
Which Mazda CX-9 years have sudden loss of power problems?
The model years with the most reports are 2010 (7 complaints), 2017 (5 complaints) and 2012 (4 complaints).
How much does it cost to fix sudden loss of power on the Mazda CX-9?
Owners who mentioned a price put the repair at about $5,000 (median of 5 complaints that include a dollar amount). Costs vary with mileage, warranty and where the work is done.
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