What does it mean if the Malfunction Indicator Lamp (MIL) flashes once per second?

When the Malfunction Indicator Lamp (MIL) flashes once per second, it signifies a severe misfire condition. This behavior indicates that the engine is experiencing an issue that could result in excessive emissions or potential damage to the catalytic converter. A misfire occurs when one or more of the engine's cylinders fail to fire properly, which can lead to a range of problems, including reduced engine performance and increased fuel consumption.

In this case, the flashing light serves as a warning to the driver that immediate action is required to avoid further damage. Addressing a severe misfire promptly is essential to maintaining the vehicle's performance and adhering to emissions standards. The other response options correspond to different scenarios. For example, a minor issue detected would not trigger a flashing indicator, and system checks or sensor failures would usually result in a steady MIL rather than a flashing one. Understanding the implications of the MIL's signaling helps drivers manage their vehicle's health proactively.