2021 Mazda CX-9 engine problems
19 owner complaints filed with NHTSA name the engine on the 2021 Mazda CX-9 — 53% of all complaints for this model year.
What owners report
“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…”
filed Jul 23, 2026
“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…”
filed Jul 12, 2026
“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…”
filed Jun 18, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
This Service Alert supersedes the previously issued SAs listed below. The changes are noted in Red text. SA-017/25 12/16/25, 09/08/25, 07/14/25, 05/15/25 and 03/21/25 DESCRIPTION Mazda Connect Frequently Asked Questions…
SA-042-26 · Service Bulletin/Repair Instructions · issued Jul 1, 2026This SA supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-061/25 12/17/25 DESCRIPTION If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s)…
SA-041-26 · Service Bulletin/Repair Instructions · issued Jun 19, 2026Valve Stem Seals Class Action Settlement Program for Excessive Oil Consumption and Oil Consumption Powertrain Warranty Extension Special Service Program SSPD5. Updated April 28, 2026 – Related oil part number for…
SSPD5 Parts Warr b · Warranty Program/Extension · issued Apr 29, 2026
Engine problems in other CX-9 years
| Year | Reports | Share |
|---|---|---|
| 2020 CX-9 | 5 | 26% |
| 2019 CX-9 | 22 | 42% |
| 2018 CX-9 | 73 | 58% |
| 2017 CX-9 | 43 | 70% |
| 2016 CX-9 | 64 | 62% |
| 2015 CX-9 | 17 | 49% |
| 2014 CX-9 | 19 | 35% |
| 2013 CX-9 | 17 | 25% |
| 2012 CX-9 | 25 | 11% |
| 2011 CX-9 | 15 | 9% |
| 2010 CX-9 | 23 | 12% |
| 2009 CX-9 | 4 | 7% |
Other reported problem areas on the 2021 Mazda CX-9
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.