What does a "Check Engine" light typically indicate?

The "Check Engine" light is designed to alert the driver to a problem detected by the vehicle's onboard diagnostics system. When illuminated, it often indicates that there is a fault affecting the vehicle's emissions system. This can include issues such as a malfunctioning oxygen sensor, catalytic converter failure, or problems with the fuel injection system. The regulation of emissions is critical for meeting environmental standards, and malfunctions in these systems can lead not only to increased pollution but also to decreased engine performance and efficiency.

Thus, the presence of the "Check Engine" light is a signal that a diagnostic trouble code has been generated, which needs to be read and understood in order to identify the specific issue. This focus on emissions-related faults underscores the importance of environmental compliance and the role of the onboard diagnostics in maintaining vehicle performance and contributing to cleaner air.