What does it mean when the engine fault indicator light turns yellow?

[LailaFitz]

Possible reasons for the engine fault indicator light turning yellow are as follows: 1. Poor fuel quality: Fuel quality is the primary factor causing the engine fault light to illuminate. The anti-knock property of gasoline is indicated by its octane rating—the higher the octane number, the better the anti-knock performance. For example, 97-octane gasoline has an octane rating of no less than 97. Leaded gasoline can cause lead poisoning in oxygen sensors. Poor fuel quality is the main cause of insufficient engine combustion, leading to the engine fault light turning on. 2. Abnormal fuel pressure: If the fuel pump's supply pressure fails to reach the required level, it can result in inadequate atomization by the fuel injectors, affecting the engine's normal operation. When combustion is insufficient, the engine fault light will turn yellow.