What Causes the Engine Yellow Light to Flash?
1 Answers
When the engine yellow light flashes, it indicates a fault in the car's engine. Below are the reasons and solutions for the engine yellow light coming on: 1. Poor or substandard gasoline quality: Filling up at non-standard gas stations with low-quality gasoline can lead to incomplete combustion of the air-fuel mixture during engine operation, triggering the engine fault light. While this does not affect driving safety, it can harm the engine to some extent. 2. Oxygen sensor failure: Modern cars are equipped with two oxygen sensors, one before and one after the three-way catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine conditions, and the ECU adjusts fuel injection and calculates ignition timing based on this signal. The rear sensor primarily monitors the performance of the three-way catalytic converter. Therefore, if the oxygen sensor is damaged or its connector is faulty or loose, it can cause the air-fuel mixture to become too lean or too rich, triggering the fault light. In reality, the oxygen sensor is a highly durable component and can last for 3 years or longer with good fuel quality. So, if the fault light comes on in a new car, it's worth checking if the oxygen sensor connector is loose. 3. Mass air flow (MAF) sensor failure: The MAF sensor, also known as the air flow meter, measures the amount of air intake and converts it into an electrical signal sent to the ECU. Based on the optimal air-fuel ratio, the ECU determines the fuel injection amount. If the MAF sensor or its wiring fails, the ECU will not receive the correct air intake signal, leading to improper fuel control and causing the air-fuel mixture to become too lean or too rich, resulting in poor engine performance. Although a faulty MAF sensor may not prevent the engine from starting, issues like unstable idling, poor acceleration, backfiring, and black smoke from the exhaust are highly likely.
