2021 Mazda Mazda3: engine and transmission complaints
HIGH COMPLAINT SIGNAL
50%
22 of 44 relevant owner complaints are about the engine, transmission or fuel system
50% of relevant owner complaints filed with NHTSA on the 2021 Mazda Mazda3 are about the engine, transmission or fuel system. That is a model-level pattern, not bad luck.
Worse than 64% of the 1,230 model years we track (2010–2023).
Excludes 5 airbag, lighting and seat-belt recall complaints that would otherwise mask the signal (unadjusted: 45%).
The percentage is each model year's drivetrain complaint share. No elevated signal describes the model year, not any one car; a well-kept example of a flagged model can still be the right buy, and any of these still needs an inspection.
What owners reported
POWER TRAIN01/25/2026
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 confirm the problem …
POWER TRAIN05/27/2025
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 very helpful with th…
ENGINE04/23/2025
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.
Three of 22 drivetrain complaints. The full report shows more, with quotes about the engine in the car you are looking at first.
Recall campaigns on this model year (1)
TIRES:VALVE
Mazda North American Operations (Mazda) is recalling certain 2021 Mazda3 and CX-30 vehicles. Air may suddenly leak from the tire air valve.
This does not say whether a particular car has an open, unrepaired recall. That depends on the VIN.
Before you buy a 2021 Mazda Mazda3
Ask the seller whether the engine has ever been repaired or replaced, and whether the car has shown stalling, loss of power, rough idle, oil consumption or a check-engine light.
Drive it from a cold start and long enough to warm up. Many engine faults hide once the car is warm.
Get an independent pre-purchase inspection from a mechanic you choose, and tell them to focus on the engine.
1 recall campaign on this model year. Whether a specific car still has one open depends on the VIN; the report checks that.
Ask for service records. A engine already replaced under warranty is a different car from one that was not.
Have the VIN?Paste it and get the full report for that car. First report free, then a 30-day pass covers a whole car search.
Experimental model-level information. This is not a vehicle inspection, vehicle-history
report, financial advice or purchase recommendation. It describes patterns across a model year, not the condition
of any individual vehicle.