Last updated: 2026-07-25

2021 Mazda CX-9
RELIABILITY SCORE: 77/100 (GOOD)

2021 Mazda CX-9 Reliability Report

The 2021 Mazda CX-9 scores 77/100 ("Good"). With 1 recall and 35 owner complaints, reliability is acceptable but not class-leading.

Recalls

1

Complaints

35

Complaint Rate

10.1per 10,000 sold

Est. Repair Cost

$539

Annual Fuel Cost

$2,500–$2,600

Detailed Score Breakdown

Complaint Severity64/100

Component-weighted complaints normalized by sales volume

Repair Costs80/100

Independent repair cost ratings

Recall Impact88/100

Recall count weighted by severity

Issue Diversity84/100

Breadth of reported problem categories

The Verdict

Consider

Acceptable reliability — worth considering with a pre-purchase inspection.

Top Issues to Watch

  • ENGINE (17)
  • POWER TRAIN (2)
  • SERVICE BRAKES (2)

Generation & Refresh (US)

Post-Redesign (Year 6)

2021 is year 6 of the Second generation (TC; 2016).

  • Redesigned for the 2016 model year.
  • Well-established in its generation — most early issues should be resolved.
  • 2nd generation CX-9 (US).

What this means for buyers

Well into the generation cycle — most design and manufacturing issues should be resolved by now.

2016: Second generation (TC; 2016) Launch

Generation start — new platform.

2021: This Model Year

2021 is year 6 of the Second generation (TC; 2016).

Should You Buy the 2021 Mazda CX-9?

At 77/100, the 2021 Mazda CX-9 lands in "Good" territory — acceptable, but not class-leading. 2021 is year 6 of the Second generation (TC; 2016).

Owners log 35 complaints on this model year — enough to suggest attention is needed, but no single failure mode dominates yet.

Get a pre-purchase inspection on any used example, with extra attention to engine (17). An extended warranty is worth pricing out.

Compared to the 2022 Mazda CX-9, which scored 4 points higher. See also the 2020 Mazda CX-9 for an earlier comparison.

Pros

  • +Acceptable reliability score
  • +$245 cheaper to maintain than avg midsize SUV
  • +Low major repair risk (10%)
  • +Low recall count

Cons

  • ENGINE issues reported (17 complaints)
  • UNKNOWN OR OTHER: Owners of the 2021 Mazda CX-9 report several issues related to vehicle... (4 complaints)

Compare 2021 Mazda CX-9 With

Common Problem Categories

Safety

LOW RISK
  • 1 manufacturer recall issued

Other

HIGH RISK
  • ENGINE (17)
  • UNKNOWN OR OTHER (4)

See detailed breakdown by component ↓

Recall Overview

1

recall on record

The 2021 Mazda CX-9 carries 1 recall — a low count. Authorized dealers repair any open recall free of charge, regardless of warranty status.

NHTSA.gov →

Complaint Breakdown

10.1

per 10,000 sold

Segment avg: 16.7

LowAvgHigh
Moderate

Safety Incidents

6

Crashes

0

Fires

1

Injuries

0

Deaths

NHTSA 5/5 Stars

Data sourced from NHTSA complaint filings and manufacturer recall notices. Complaint narratives are owner-reported.

2021 Mazda CX-9 Recall Details

1 recall has been issued for the 2021 Mazda CX-9. All recall repairs are performed free of charge at authorized dealerships.

21V7500002021-09-27

SEATS, SEAT BELTS

Mazda North American Operations (Mazda) is recalling certain 2020-2021 CX-9 vehicles equipped with 60/40 split bench second-row seats. The left-side second-row seat may unexpectedly slide forward during a crash. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 210, "Seat Belt Assembly Anchorages."

Consequence

A seat that slides forward during a crash can transfer excessive force onto a belted occupant, increasing their risk of injury.

Remedy

Dealers will replace the internal parts of the affected second-row seats, free of charge. Owner notification letters were mailed November 4, 2021. Owners may contact Mazda customer service at 1-800-222-5500, Option 4. Mazda's number for this recall is 5221I.

VIN History Report

Buying a used 2021 Mazda CX-9? Check its history first

Every 2021 Mazda CX-9 has a different past. A VIN check reveals hidden accidents, title problems, odometer rollbacks, and open recalls that reliability scores can't show you.

Affiliate link — we may earn a commission at no cost to you. No VIN? Just hit “Check VIN” to look one up.

  • Accidents
  • Open Recalls
  • Title History
  • Odometer Rollback

2021 Mazda CX-9 NHTSA Safety Ratings

Overall Safety Rating

Overall safety rating: 5 out of 5
Crash Test Results by Configuration (expand)

Gas Powertrain

Driver: 4/5Passenger: 4/5

Rollover risk: 15.1%

Safety Technologies

Dynamic Head Restraints (Not Available)Head Restraint (Driver, Front Passenger, Rear Seat, 3rd row)Advanced Belt Feature (Standard)Adjustable Upper Belt Anchorage (Driver, Front Passenger)Seat Belt Reminder System (Driver, Front Passenger, Rear Seat, 3rd row)Frontal Air Bag (Driver, Front Passenger)Curtain (Driver, Front Passenger, Rear Seat, 3rd row)Torso/Pelvis (Driver, Front Passenger)Knee (Not Available)Additional Air Bags (None)Meets Side Air Bag Out-of-Position Requirements (Yes)LATCH Locations (Rear Seat)Safety Power Windows (Anti-Pinch) (Standard)Safety Power Windows (Anti-Pinch) locations (Driver, Front Passenger, Rear Seat)
View full safety data on NHTSA.gov →

Mazda CX-9Repair Costs & Maintenance

Maintenance Rating

4Maintenance rating: 4 out of 5

Based on NHTSA complaint patterns, recall severity, and publicly available cost benchmarks.

Est. Annual Maintenance

$539

vs $784 avg for midsize SUV

vs $652 avg for all vehicles

Repair Frequency

0.6

unscheduled repair visits per year

Severe Repair Probability

10%

chance of a major repair

Annual Cost Comparison

CX-9
$539
Category Avg
$784
All Vehicles
$652

Category-level averages derived from publicly available industry reports (AAA, CarMD). Model-level estimates produced by Auto Reliability Index.

MPG & Annual Running Costs

Gas

23–24 MPG

Running cost: $3,050–$3,150/yr

Fuel + repair

20–22 city / 26–28 hwy MPG

Running cost includes EPA fuel-cost estimate and independent repair-cost data (repair cost estimated at model level). Excludes routine maintenance, depreciation, and insurance. Data as of 2021 EPA label cycle.

Gas trims
TrimDriveTrans.CityHwyCombFuel Cost
CX-9 2WD 2.5L 4-cylFront-Wheel DriveAutomatic (S6)222824$2,500
CX-9 4WD 2.5L 4-cyl4-Wheel DriveAutomatic (S6)202623$2,600

Used Buying Checklist

Key things to inspect or verify before purchasing a 2021 Mazda CX-9.

  • Check for excessive oil consumption by inspecting oil level and checking for low oil warning lights

  • Verify completion of any valve stem seal repairs under the class action settlement

  • Inspect brakes for persistent clicking or squeaking noises, even after recent replacements

  • Test the airbag system functionality and inspect for any previous deployment issues

  • Ensure the vehicle does not exhibit unexpected acceleration or loss of power during test drives

2021 Mazda CX-9 Common Problems by Component

35 owner complaints grouped by vehicle system.

17
4
5
ENGINE (17)UNKNOWN OR OTHER (4)POWER TRAIN (2)SERVICE BRAKES (2)AIR BAGS (2)BACK OVER PREVENTION (1)FORWARD COLLISION AVOIDANCE (1)SUSPENSION (1)Other (5)

ENGINE

17 complaints

Owners report that the 2021 Mazda CX-9 frequently experiences excessive oil consumption, with many noting the need to add approximately one quart of oil every 2,500 to 3,500 miles. Complaints often mention the low oil warning light activating and the discovery of low oil levels upon inspection. Some owners attribute the issue to defective valve stem seals, as referenced in technical service bulletins and a class action lawsuit. The majority of these issues are reported around 10,000 to 50,000 miles. While no direct safety incidents such as crashes or fires are described, the potential for engine damage or failure due to oil loss is a concern for owners. This information is particularly relevant for used car buyers considering this model.

17 complaints total

UNKNOWN OR OTHER

4 complaints

Owners of the 2021 Mazda CX-9 report several issues related to vehicle malfunction and unexpected behavior. Multiple complaints describe sudden vehicle stops due to malfunctions in systems such as i-ACTIVESENSE, Dynamic Stability Control, and the engine, with incidents occurring at least twice for one owner. Another owner reports excessive oil consumption beginning after the first oil change. Additionally, there are concerns about the vehicle's auto-locking feature, which can engage unexpectedly, potentially locking occupants or items inside without warning. These issues present potential safety risks, including the risk of collisions from sudden stops and the danger of being unable to access the vehicle in emergencies.

4 complaints total

POWER TRAIN

2 complaintsSafety-related

Owners of the 2021 Mazda CX-9 report issues related to the powertrain, specifically involving cylinder compression loss and unintended acceleration. One complaint involves a loss of compression in a cylinder, attributed to a valve stem seal issue, with the owner noting this occurred at approximately 60,083 miles. Another complaint describes the vehicle unexpectedly accelerating forward while in reverse, resulting in a crash that caused injury, with no prior warning indicators or brake assist activation. These reports highlight potential safety implications, including loss of vehicle control and injury risk, particularly in parking scenarios. Buyers should be aware of these issues, especially regarding the valve stem seal settlement and its coverage limitations.

2 complaints total1 crash1 injury
SERVICE BRAKES (2 complaints)

SERVICE BRAKES

2 complaintsSafety-related

Owners of the 2021 Mazda CX-9 report persistent issues with the service brakes. One complaint describes ongoing clicking and squeaking noises from the brakes, even after replacement of both front and rear brakes and rotors at around 22,000 miles, with the issue persisting up to 49,000 miles. Another report details a failure of the brakes to maintain pressure during a hard stop, leading to a crash when the brakes unexpectedly released. This incident also involved a failure of the driver's side airbag to deploy. The complaints highlight potential safety risks, including a crash due to brake malfunction, and suggest that these issues may persist despite dealer interventions.

2 complaints total1 crash
AIR BAGS (2 complaints)

AIR BAGS

2 complaintsSafety-related

Owners of the 2021 Mazda CX-9 report issues with airbag deployment in crash scenarios. One complaint describes a frontal collision at 10-20 mph where the driver-side airbag failed to deploy, rendering the vehicle undrivable post-collision. Another report highlights that during an airbag deployment, the right curtain airbag caused the rear passenger handle and hook to splinter into sharp projectiles, posing a risk to occupants. These incidents involve crashes, indicating potential safety implications with the airbag system. Such reports may be relevant for used car buyers considering the safety performance of the airbag system in this model.

2 complaints total2 crashes
BACK OVER PREVENTION (1 complaints)

BACK OVER PREVENTION

1 complaintSafety-related
2025-12-08Crash reported

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

FORWARD COLLISION AVOIDANCE (1 complaints)

FORWARD COLLISION AVOIDANCE

1 complaint
2024-09-03

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)

SUSPENSION (1 complaints)

SUSPENSION

1 complaint
2024-08-15

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.

VEHICLE SPEED CONTROL (1 complaints)

VEHICLE SPEED CONTROL

1 complaint
2023-08-01

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.

WHEELS (1 complaints)

WHEELS

1 complaint
2023-07-08

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.

When Do 2021 Mazda CX-9 Problems Start?

Based on owner complaint patterns, here's when common issues tend to appear.

10,000–50,000 milesEngine oil consumption

Best & Worst Mazda CX-9 Years

Comprehensive reliability analysis based on NHTSA data, owner complaints, and historical performance.

Best Mazda CX-9 Years to Buy

The best Mazda CX-9 year is 2023 with a reliability score of 81/100, rated excellent. Other strong picks include 2022 (81/100) and 2020 (78/100).

Mazda CX-9 Years to Avoid

The worst Mazda CX-9 year is 2018 with a score of 66/100, primarily due to engine (60) issues.

Mazda CX-9 Reliability Score Trend

Mazda CX-9 reliability has improved in recent years, with newer models scoring an average of 80/100 compared to 72/100 for older years.

Scores 0–100. Higher is better. Current year highlighted.

Mazda CX-9 reliability scores by year
YearScoreRating
201866/100Good
201973/100Good
202078/100Good
202177/100Good
202281/100Excellent
202381/100Excellent

Mazda CX-9 Reliability Compared to Other Years

Reliability scores compared across model years
YearScorevs Prior YearRatingRecallsComplaints
202381/1000Excellent012
202281/100+4Excellent09
2021(selected)77/100-1Good135
202078/100+5Good119
201973/100+7Good252
201866/100Good2125

Frequently Asked Questions

Is the 2021 Mazda CX-9 reliable?
The 2021 Mazda CX-9 has a "Good" reliability rating with a score of 77/100. It is reasonably reliable with 1 recall and 35 owner complaints, though some issues have been reported.
What are the most common problems with the 2021 Mazda CX-9?
The most commonly reported problems with the 2021 Mazda CX-9 include: ENGINE (17 complaints), UNKNOWN OR OTHER (4 complaints), POWER TRAIN (2 complaints), SERVICE BRAKES (2 complaints), AIR BAGS (2 complaints). These issues were identified from owner complaints analyzed by Auto Reliability Index.
How many recalls does the 2021 Mazda CX-9 have?
The 2021 Mazda CX-9 has 1 recall on record. Recalls are safety or compliance fixes issued by the manufacturer and repaired at no cost at authorized dealerships.
Is the 2021 Mazda CX-9 expensive to maintain?
The 2021 Mazda CX-9 has estimated annual repair costs of $539/year, which is $245 less than the midsize SUV average of $784. With a reliability score of 77/100, some repairs may be needed, but overall ownership costs are manageable.

Don’t buy a 2021 Mazda CX-9 without checking its VIN first — hidden accidents, title issues, and open recalls could cost you thousands.

Affiliate link — we may earn a commission at no cost to you.

Look Up a VIN →

How We Calculate Reliability Scores

Auto Reliability Index scores are calculated on a 0–100 scale using a weighted formula that combines multiple public data sources. Each factor is weighted based on its predictive value for real-world ownership experience.

Key Ranking Factors

1

Complaint Severity

NHTSA owner complaints weighted by component category (e.g., powertrain, safety systems, electronics, cosmetic) — safety-critical issues carry more weight than cosmetic ones. Adjusted for sales volume so high-volume models aren't unfairly penalized.

2

Repair Costs

Independent reliability ratings based on repair frequency, average repair costs, and severity of typical repairs for each model.

3

Recall Impact

Number of NHTSA recalls weighted by severity. “Stop driving” and fire-risk recalls are penalized more heavily than minor software or labeling recalls.

4

Issue Diversity

Measures how many major vehicle systems (engine, transmission, electrical, braking, etc.) have recorded complaints. A vehicle with issues spread across many systems may indicate systemic quality issues.

Scores are grouped into four tiers:

  • 80–100: Excellent— Top-tier reliability, minimal issues
  • 60–79: Good— Reliable with some minor concerns
  • 40–59: Mixed— Notable issues, research before buying
  • 0–39: Risky— Significant problems, proceed with caution

Data is sourced from NHTSA recall records, owner complaint filings, and independent repair databases. Scores are recalculated as new data becomes available. While the weighting model is proprietary, all underlying data sources are public and traceable.

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