When should a vehicle with a check engine light on be serviced?

When a vehicle has a check engine light illuminated, it indicates that the vehicle's onboard diagnostics system has detected a potential issue. Servicing the vehicle in this case is crucial because ignoring the light can lead to more significant problems down the line. The most effective course of action is to diagnose the issue to determine the underlying cause of the light being on. This allows for proper identification and repair of any faults, preventing further damage to the vehicle and ensuring optimal performance.

The check engine light could signal various issues, from minor problems such as a loose gas cap to more serious engine or transmission issues. By diagnosing it promptly, one can take informed steps towards addressing the problem, avoiding costly repairs in the future, and ensuring the vehicle operates safely and efficiently. Therefore, seeking a diagnosis when the check engine light is on is the appropriate response.