What are the reasons for the Mazda 3 Axela engine warning light to illuminate?

[StMarley]

The engine warning light may illuminate during power-on self-test or under other circumstances. The power-on self-test is an indication that the vehicle is monitoring the status of all sensors before driving. Generally, if the engine is not started after power-on, the light will turn off by itself after about 3 seconds. In other cases, if the EPC indicator light remains illuminated for an extended period after the vehicle is started, the possible causes include faults in the engine intake system, throttle failure, fuel system issues, engine malfunction, ECU control unit failure, or brake light problems. Below is a detailed explanation of each possible fault: Sensor Issues: Sensors include coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors. When these sensors are damaged, have poor contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data, which may trigger the engine warning light. Solution: If such issues occur, promptly visit a repair center for professional inspection to eliminate potential safety hazards. Maintenance Issues: Poor engine maintenance is the most common cause of the engine warning light illuminating. Vehicles have specific maintenance cycles. If maintenance is neglected and combined with poor driving habits, the engine's workload increases, eventually causing the warning light to illuminate. Solution: Follow the maintenance schedule in the vehicle's manual, including time or mileage intervals, to ensure comprehensive maintenance and rule out non-maintenance-related issues. Fuel Quality Issues: This refers to both fuel and engine oil. Vehicles require specific fuel grades, and engine oil can be semi-synthetic or fully synthetic. Manufacturers typically recommend the appropriate fuel grade and oil type. Failure to follow these recommendations may lead to engine wear and trigger the warning light. Solution: Use the recommended fuel grade and engine oil type for the vehicle. Poor Combustion of Air-Fuel Mixture: Faulty spark plugs, fuel pump issues, or clogged fuel lines can cause poor combustion of the air-fuel mixture, leading to engine carbon buildup or knocking. The oxygen sensor detects these issues and reports them to the ECU, triggering the warning light. Intake Issues: Engine combustion requires proper air intake, where the air filter plays a crucial role. A dirty or clogged air filter can restrict airflow, eventually leading to intake blockage and triggering the warning light. Solution: Regularly clean or replace the air filter to ensure proper intake system operation. Turbocharger Issues: Problems with the intake boost system or turbocharger can also cause the engine warning light to illuminate. Common issues include turbocharger failure, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black exhaust smoke. Solution: Visit a 4S shop for inspection and replacement of the turbocharger. In most cases, repair is not cost-effective, and replacement is recommended. Exhaust Issues: Faults in the rear oxygen sensor, catalytic converter, or exhaust camshaft and bearings can trigger the warning light. The most common issue is catalytic converter failure, often caused by physical damage or fuel system problems. Solution: Use lead- or silicon-based lubricants for catalytic converter maintenance and cleaning. Anti-Theft System Issues: If the vehicle's anti-theft system malfunctions or the anti-theft controller is incompatible with the engine ECU, the engine may not operate properly, and the warning light may illuminate. Solution: Seek professional assistance at a repair shop, as this issue cannot be resolved individually. Engine Misfire: This occurs when one or more cylinders fail to operate properly, leading to symptoms such as power loss, difficulty starting, or unstable idling. Solution: Identify and replace faulty cylinder components. If internal mechanical damage is present, major repairs may be required.