Mazda MAZDA3 check engine light comes on

Filed Oct 13, 2026 · Engine, Fuel system · 100,000 miles · TX

The contact owns a 2018 Mazda Mazda3. The contact stated that while driving uphill at 45 MPH, the vehicle sputtered, hesitated to accelerate, and the check engine warning light illuminated. When the contact firmly depressed the accelerator pedal, the engine made a knocking noise, and the vehicle stalled. Diagnostic testing at AutoZone retrieved DTC related to the knock sensor. The vehicle underwent a tune-up, and the knock sensors and ignition coils were replaced; however, the failure persisted. While driving, the vehicle hesitated and failed to exceed 40 MPH. The contact pulled over, restarted the vehicle, and drove to the residence with the hazard lights activated. The vehicle was taken to the dealer, where the federal safety agency Campaign Number: 23V487000 (Back Over Prevention) was completed. The contact associated the engine hesitation and stalling failures with the federal safety agency Campaign Numbers: 17V745000 (Engine and Engine Cooling) and 21V875000 (Fuel System, Gasoline); however, the dealer informed the contact that the VIN was excluded from both recalls. The manufacturer was notified of the failure by phone. The failure mileage was approximately 100,000.

Filed Jun 14, 2026 · Fuel system · RI

The fuel tank leaks fuel at a full tank and smells of gas in the cabin until about 3/4 tank. Car was dripping a large puddle of gas inside of a parking garage. Problem has been reproduced by my mechanic even after replacing the fuel pump retaining ring. It has not been inspected by the manufacturer or police. CEL did not come on until recently reporting a very small EVAP leak. Inside the car and the surrounding area would smell of gasoline even if there was no leak in the ground.

Filed Jan 6, 2026 · Steering · 195,081 miles · CA

The contact owns a 2007 Mazda Mazda3. The contact stated that while driving 5 MPH and making a turn, the steering wheel was difficult to turn to the left or the right. The check engine warning light was illuminated and flashing. The contact stated that the steering then seized. While checking the website, the contact associated the failure to the federal safety agency Campaign Number: 10V374000 (Steering). The vehicle was taken to the local dealer, who confirmed there was no recall coverage on the VIN related to the failure. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case, and confirmed there was no recall coverage for the failure. The vehicle was not diagnosed or repaired. The failure mileage was approximately 195,081.

Filed Dec 24, 2025 · Engine, Fuel system · CA

Catalytic converter keeps giving me check engine

Filed Nov 24, 2025 · AL

I was driving it and randomly the AT and TC , and check engine light came on and the car went into limp mode, after doing some research it appears to happen to all 2009-2011 Mazda3's and it's a safety hazard. It's a safety hazard because of when it's stuck in limp mode sometimes if your at a light or something it'll start shifting and if you're not holding the brake completely down it will make the car lurch forward like 2-3 feet more if you don't react fast enough. This is a serious problem as it can cause a wreck. And you never know when it's going to happen there will be no symptoms it will just go into limp mode sometimes it'll rapidly go in and out and I'm sure that's causing damage to my transmission. Please make Mazda recall the TCM part and replace it. Thank you so much for taking the time to read my complaint/safety issue. Have a good day or night!!!

Filed Nov 19, 2025 · Electrical, Engine · TX

My 2018 Mazda 3 has an intermittent electrical failure on the high-speed CAN network that causes multiple safety-critical systems to fail while driving. When the fault occurs, the dash lights up with warnings for powertrain, ABS/traction, lane departure, collision-avoidance, TPMS, immobilizer, and the check-engine light. The car also hesitates or “lurches” between 15–30 mph during these events. At one point in 2024, the vehicle went into limp mode on the freeway, creating a safety hazard. These failures are intermittent but repeatable. Diagnostic scans from 2023–2025 show multiple U-codes for lost communication between control modules; two later became permanent. The issue appears unrelated to any one component and affects many systems at once. The vehicle has been to every Mazda dealership in the North Texas region (Mesquite, Freeman, Hiley, Norm Reeves, Town North). All performed only basic scans; none completed a full CAN-bus or wiring-harness diagnostic. Town North kept the vehicle for six weeks (Sept–Oct 2025), replaced a coil and spark plugs, performed a camera calibration and a TCM update, but the network failures returned within 38 miles. We sought independent inspection only after dealerships repeatedly refused diagnosis whenever the warning lights were not on at the moment of arrival. In November 2025, a technician found significant internal corrosion inside the negative battery cable; touching the cable reproduced the full failure immediately. The corrosion extends deep into the wire sheathing. This appears to be an electrical defect affecting CAN communication and power/ground integrity. When the fault occurs, multiple safety systems disable at once and the vehicle behaves unpredictably. Mazda Corporate has declined further assistance, and the defect remains unresolved. I am filing this report because this is a recurring safety issue that may affect other vehicles of the same model and year.

Filed Oct 20, 2025 · Engine, Transmission · CA

What component or system failed or malfunctioned, and is it available for inspection upon request? The high-pressure fuel pump failed. This component failure prevents the car from starting or staying running. The check engine code confirmed the high-pressure fuel pump failure. The failed component is currently at the Mazda dealership and is available for inspection upon request. How was your safety or the safety of others put at risk The car suddenly stalled while driving on the roadway, creating a dangerous situation. If this had happened on the freeway or in fast-moving traffic, it could have led to a serious accident. Losing power and control of the vehicle at higher speeds poses a major safety risk to both the driver and surrounding vehicles. I was fortunate that the failure occurred on a city street rather than on the freeway. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The Mazda dealership inspected the vehicle and confirmed that the high-pressure fuel pump had failed, which was also verified by the check engine code. This failure caused the stalling and starting issues. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle was inspected by an authorized Mazda dealership, which diagnosed and confirmed the high-pressure fuel pump failure. It has not been inspected by police or insurance representatives. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? Before the final failure, the car was hesitant to start, and after it stalled, the check engine light appeared. There were no prior warning messages or signs before the car suddenly stalled while driving. Additional details: The car is only seven years old with approximately 52,000 miles, and it is concerning that such a critical component would fail this early.

Filed Sep 26, 2025 · Electrical, Engine · 197,687 miles · NY

Odometer Fraud. The contact purchased a 2014 Mazda Mazda3. The contact stated that the vehicle was making an abnormal growling sound. The check engine warning light was illuminated. The contact discovered a mileage discrepancy after the purchase. The vehicle was a private sale. At the time of purchase, the vehicle mileage was 140,000. The vehicle was taken to the local dealer, where it was diagnosed and determined that the motor mounts needed to be replaced. It was later discovered that the Title mileage was 197,687.

Filed Sep 11, 2025 · Fuel system · VT

Anytime the tank was filled with gas there was a strong smell of gasoline vapors that persisted for several days. The car was a few months past its warranty on emissions issues and so I was charged about $1500 to replace a cracked fuel pump and fuel vent that was stuck open. The mechanic also said that the check engine light should have warned me about the problem but that neither the dashboard light nor his diagnostic equipment was triggered by the defect. He suspects the car's computer is programmed to avoid drawing attention to the problem. Had the light been working I would likely have caught the problem while it was still under warranty.

Filed Apr 23, 2025 · Engine · PA

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.