What Causes the Car Engine Malfunction Light to Stay On?
1 Answers
Car engine malfunction light stays on due to reasons such as substandard fuel quality, oxygen sensor failure, air flow meter malfunction, engine knocking, water temperature sensor damage, and engine misfire. Substandard fuel quality: Primarily because during engine operation, poor-quality fuel leads to incomplete combustion of the air-fuel mixture, failing to meet the engine's fuel performance requirements, thus triggering the malfunction light. It is necessary to refuel with quality-compliant fuel to satisfy the engine's needs. Oxygen sensor failure: If the oxygen sensor is damaged or the sensor connector is faulty or loose, it can cause the air-fuel mixture to be too lean or too rich, leading to the malfunction light illuminating. Replacing the oxygen sensor is required to ensure normal engine operation. Air flow meter malfunction: If the air flow meter or its circuit fails, the ECU will not receive the correct air intake signal, preventing proper fuel control. This results in a mixture that is too lean or too rich, causing symptoms like rough idling, poor acceleration, increased fuel consumption, and black smoke from the exhaust, thereby affecting engine performance. Immediate inspection and repair at a 4S shop or repair shop are necessary. Engine knocking: Often manifested as poor vehicle performance, excessive engine noise, and in severe cases, accompanied by knocking sounds. Immediate inspection and repair at a repair shop are required; ignoring it and continuing to drive is not advisable. Water temperature sensor damage: If the water temperature sensor fails to send cold engine status information, it will cause the air-fuel mixture to become too lean, leading to abnormal engine operation. Repair or replacement of the water temperature sensor at a repair shop is needed. Engine misfire: Engine misfire can lead to symptoms such as high fuel consumption, black smoke, poor acceleration, increased noise, noticeable intermittent exhaust emissions, and exhaust pipe shaking. Additionally, it can easily cause the vehicle to stall.
