AutoUtility currently tracks 49 official NHTSA owner defect complaints for the 2021 Mazda Mazda3. Engine & Cooling issues are the most frequently reported category, appearing in 17 complaints (34.7% of submitted records). Among these NHTSA complaint records, 2 filings cite a crash, 2 cite a fire, 1 reports one or more injuries.

Key Problem Findings
  • Total NHTSA Complaints: 49 reports
  • #1 Reported Problem Area: Engine & Cooling (17 reports • 34.7% of submitted complaints)
  • Secondary Problem Areas: Driver Assistance & Safety Tech (10), Electrical System (6)
  • Crash-Citing Complaints: 2 filings
  • Fire-Citing Complaints: 2 filings
  • Complaints Reporting Injuries / Fatalities: 1 injury filings • 0 fatality filings
Reporting Methodology: Statistics describe unverified consumer submissions voluntarily filed with NHTSA. Complaint volume is not normalized for vehicle sales volume or miles driven. Multiple components can be cited within a single owner complaint submission.
Total Complaints
49
Submitted to NHTSA ODI
Crash-Citing Complaints
2
Filings citing a collision
Fire-Citing Complaints
2
Filings citing smoke or fire
Complaints Reporting Injuries
1
Filings citing one or more injuries
Complaints Reporting Fatalities
0
Consumer filings citing fatalities

Most Reported Problems for 2021 Mazda Mazda3

Top automotive subsystem defect categories ranked by unique owner complaint volume in federal records

#1 Problem Area 34.7% of complaints

Engine & Cooling

17 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
#2 Problem Area 20.4% of complaints

Driver Assistance & Safety Tech

10 owner complaints submitted to NHTSA ODI
⚠️ 1 crash report
#3 Problem Area 12.2% of complaints

Electrical System

6 owner complaints submitted to NHTSA ODI
⚠️ 1 crash report 🔥 2 fire reports
#4 Problem Area 10.2% of complaints

Air Bags & Restraints

5 owner complaints submitted to NHTSA ODI
⚠️ 1 crash report 🩹 1 injury report entry
#5 Problem Area 8.2% of complaints

Brakes & Traction Control

4 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
Domain Share Note: Share percentage represents the proportion of unique complaint filings referencing each vehicle system. Because single complaints may cite multiple systems (such as engine and electrical simultaneously), domain percentages represent individual category incidence and may sum to over 100%.

Recent NHTSA Owner Reports for 2021 Mazda Mazda3

Representative defect filings submitted by owners to the NHTSA Office of Defects Investigation

Powertrain & Transmission NHTSA ODI ID: #11713224
Filed: 01/25/2026

"My rear differential case cracked, anytime the four wheel drive system was engaged the entire drivetrain would lock up. Luckily we were only on side roads so going less than 30 mph if we had been on the highway when this happened we could have been in an accident or lost control. The dealer did..."

Incident Date: 02/02/2025 • Raw NHTSA Component: POWER TRAIN
Suspension NHTSA ODI ID: #11695896
Filed: 10/27/2025

"At 31,000 miles the control arm lower ball joints are torn on both lower. They must be replaced. This is a safety hazard. This should not be an issue with low mileage on this car."

Incident Date: 10/25/2025 • Raw NHTSA Component: SUSPENSION
Powertrain & Transmission NHTSA ODI ID: #11663288
Filed: 05/27/2025

"I was driving when all the sudden there was a loud bang sound. The differential housing cracked. The when awd is demanded the rear diff was was locking up instead of engaging. Luckily we were just on city streets and not on the highway as this rear wheel locking up could cause a crash. Mazda wasn't..."

Incident Date: 01/31/2025 • Raw NHTSA Component: POWER TRAIN
Engine & Cooling NHTSA ODI ID: #11656416
Filed: 04/23/2025

"Spontaneous loss of power while driving on highway. Check engine light came on. Speed limited by car. Continues to vibrate especially at idle from cold start. Code P0304 intermittently popping up."

Incident Date: 04/21/2025 • Raw NHTSA Component: ENGINE
Driver Assistance & Safety Tech NHTSA ODI ID: #11645615
Crash Cited Filed: 02/28/2025

"During the incident, the vehicle exhibited an uncontrollable malfunction—the steering wheel suddenly jerked sharply to the right while accelerating violently, leaving me unable to steer or brake effectively, the car was looking forward. The car ultimately came to a stop upon colliding with a truck..."

Incident Date: 02/05/2025 • Raw NHTSA Component: STEERING,ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL
Consumer Narrative Notice: Excerpts are sanitized text descriptions submitted by vehicle owners to the federal ODI database. They reflect the reporting consumer's observations at the time of filing and have not been independently confirmed by vehicle manufacturers or government investigators.

Complaint History for Mazda Mazda3

Reported defect complaint volume across sibling model years (2020–2025)

Model Year NHTSA Complaints Crash Reports Safety Recalls Detailed Report
2020 Mazda Mazda3 32 0 2 View 2020 Problems →
2021 Mazda Mazda3 Current Page 49 2 1 Current
2022 Mazda Mazda3 24 1 0 View 2022 Problems →
2023 Mazda Mazda3 12 3 0 View 2023 Problems →
2024 Mazda Mazda3 12 2 3 View 2024 Problems →
2025 Mazda Mazda3 7 2 1 View 2025 Problems →
Comparative Disclaimer: Complaint totals are unadjusted historical counts and are not normalized for vehicles sold, active fleet size, or total road mileage. Newer model years naturally have had less calendar exposure time to accumulate owner filings.

Detailed NHTSA Component Breakdown for 2021 Mazda Mazda3

Complete distribution of consumer defect reports across all 22 granular NHTSA system and subsystem classifications

Vehicle Component / System Total Complaints Crash Reports Fire Reports Reported Injury Entries Reported Fatality Entries
Engine NHTSA category: ENGINE 16 0 0 0 0
Air Bags NHTSA category: AIR BAGS 4 1 0 1 0
Other / Uncategorized NHTSA category: UNKNOWN OR OTHER 4 0 0 0 0
Forward Collision Avoidance NHTSA category: FORWARD COLLISION AVOIDANCE 3 0 0 0 0
Powertrain NHTSA category: POWER TRAIN 3 0 0 0 0
Electrical System NHTSA category: ELECTRICAL SYSTEM 2 0 2 0 0
SERVICE BRAKES,FORWARD COLLISION AVOIDANCE 2 0 0 0 0
ELECTRICAL SYSTEM,LANE DEPARTURE 1 0 0 0 0
ELECTRICAL SYSTEM,UNKNOWN OR OTHER 1 0 0 0 0
ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL 1 0 0 0 0
FORWARD COLLISION AVOIDANCE,LANE DEPARTURE 1 0 0 0 0
LANE DEPARTURE,FORWARD COLLISION AVOIDANCE 1 0 0 0 0
Seat Belts NHTSA category: SEAT BELTS 1 0 0 0 0
Service Brakes NHTSA category: SERVICE BRAKES 1 0 0 0 0
SERVICE BRAKES,FUEL/PROPULSION SYSTEM 1 0 0 0 0
STEERING,ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL 1 1 0 0 0
Structure & Body NHTSA category: STRUCTURE 1 0 0 0 0
STRUCTURE,ENGINE,FUEL/PROPULSION SYSTEM 1 0 0 0 0
Suspension NHTSA category: SUSPENSION 1 0 0 0 0
UNKNOWN OR OTHER,ENGINE 1 0 0 0 0
Wheels & Hubs NHTSA category: WHEELS 1 0 0 0 0
WHEELS,UNKNOWN OR OTHER 1 0 0 0 0
Data Attribution & Reporting Methodology: Complaints are unverified voluntary submissions to the NHTSA Office of Defects Investigation (ODI). Because multiple vehicle components can be cited within a single owner complaint submission, component-level rollups may sum to more than the unique complaint count (49). Injury and fatality entries in the detailed table reflect raw values entered by reporting consumers across individual submissions; they are not deduplicated casualty statistics and may include duplicate or unverified entries. Complaint volume is not normalized for sales volume or vehicle mileage and does not represent an audited component failure rate.
Official US Government Data Provenance

The complaint records on this page are retrieved directly from the NHTSA Office of Defects Investigation (ODI) public database.

Local Production Store Compiled: August 2026 • Deterministic Audited Dataset • Zero Dynamic External API Runtime Latency.