YearToAvoid

2021 Mazda CX-9 Problems, Recalls & Reliability

Verdict

Caution

Complaint Index

54/100

#7 most-complained of 14 CX-9 years

The 2021 Mazda CX-9 has 39 NHTSA complaints and a Complaint Index of 54, ranking 7th worst of 14 model years with a "Caution" verdict. Engine problems make up 54% of complaints, with a median failure mileage of 51,093 miles, plus 1 recall.

Complaints
39
Recalls
1
Crashes / fires
7 / 0
Injuries / deaths
1 / 0
NHTSA overall rating
5 / 5 ★
EPA combined MPG
23.5
21 city / 27 hwy

Top 2021 Mazda CX-9 problems

NHTSA owner complaints by component group. Groups with 15+ complaints have their own page.

  1. Engine21 (54%)
  2. Collision Avoidance & Cameras6 (15%)
  3. Other6 (15%)
  4. Brakes4 (10%)
  5. Transmission & Powertrain4 (10%)
  6. Suspension, Wheels & Tires3 (8%)
  7. Airbags2 (5%)
  8. Electrical System1 (3%)
  9. Steering1 (3%)
  10. Visibility & Wipers1 (3%)

What owners report

  • Engine reportedly consumes oil at a noticeable rate, with some owners reporting warning lights appearing roughly every 3,500 to 4,000 miles.
  • Owners describe the engine dropping about a quart of oil between checks, sometimes confirmed low by a dealership inspection.
  • Some owners report the vehicle unexpectedly accelerated forward on its own while parked or backing up, leading to collisions.
  • Brakes reportedly failed to hold or released suddenly during stops, contributing to crashes in more than one case.
  • Owners report the driver-side airbag failed to deploy during frontal collisions.
  • Backup camera distance readings were described as inaccurate, contributing to a collision with a garage door.
2021 Mazda CX-9 complaints: complaints filed per month6Feb 2021Aug 2022Feb 2023Sep 2023Jun 2024Nov 2024Jun 2026
49 complaints filed with NHTSA from Feb 2021 to Sep 2026; peak Oct 2023 (6).

2021 Mazda CX-9 recalls

1 NHTSA recall campaign list this model year.

  1. NHTSA 21V750000Sep 27, 2021Structure & Body8,648 vehicles

    Seats:mid/rear assembly

    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."

    Risk: 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.

2021 Mazda CX-9 fuel economy and fuel cost

City
21 MPG
Highway
27 MPG
Combined
23.5 MPG
Annual fuel cost (EPA)
$2,750
15,000 mi/yr
Fuel
Regular
Current regular gas
$4.32/gal
national avg.

EPA figures; median across configurations of this model year. Estimate your own cost with the fuel cost calculator.

2021 compared with other CX-9 years

Complaint Index by model year (0 = fewest issues, 100 = most)0255075100’10’11’12’13’14’15’16’17’18’19’20’21’22’23
Complaint Index: 0 = fewest issues, 100 = most, relative to other years of this model. Avoid Caution Good Best
YearVerdictIndexComplaintsRecallsMPG
2019Good3853223.5
2020Best019123.5
2021Caution5439123.5
2022Best810023
2023Best2312023

All Mazda CX-9 years: best and worst →

Frequently asked questions

Is the 2021 Mazda CX-9 reliable?
NHTSA lists 39 complaints for the 2021 CX-9, giving it a Complaint Index of 54 and a "Caution" verdict, ranking 7th worst of 14 model years for this model.
What is the top problem area for the 2021 Mazda CX-9?
Engine complaints make up 54% of all reports (21 of 39 complaints), with a median mileage at failure of 51,093 miles.
Does the 2021 Mazda CX-9 have any recalls?
Yes, one recall (campaign 21V750000) covers vehicles with 60/40 split bench second-row seats that may slide forward during a crash.
How does the 2021 CX-9 compare to other years?
The 2021 model's Complaint Index of 54 is higher than 2020 (0), 2022 (8), and 2023 (23), but lower than 2010 through 2012 and 2018, which are rated "Avoid."

Sources: NHTSA Office of Defects Investigation complaint and recall databases; U.S. EPA fuel economy data; NHTSA 5-Star Safety Ratings. Complaints are unverified owner reports.

Data updated Sep 24, 2026. Read the methodology and data sources. The Complaint Index is based on NHTSA owner complaints and recalls; it is not a reliability rating.