Why does the warning light come on after replacing spark plugs?

[DelPatrick]

Poor combustion of air-fuel mixture, sensor issues, maintenance problems, and fuel quality issues. Spark plugs are crucial components in a gasoline engine's ignition system. They introduce high voltage into the combustion chamber and create sparks by jumping the electrode gap, thereby igniting the combustible air-fuel mixture in the cylinder. Under high voltage, the air between the spark plug's center electrode and side electrode rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties. This creates a discharge channel between the gap, resulting in a "breakdown" phenomenon. At this point, the gas forms a luminous body known as a "spark." Accompanied by thermal expansion, it also produces a "crack" sound. The temperature of this electrical spark can reach 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the cylinder's combustion chamber.