What does the Service engine soon light mean in a 2000 GMC Yukon?

The "Service Engine Soon" light in a 2000 GMC Yukon indicates that the vehicle's onboard diagnostic system has detected an issue that may affect engine performance or emissions. This could be due to a variety of reasons, such as a loose gas cap, faulty sensors, or engine misfires. It's important to have the vehicle diagnosed using an OBD-II scanner to identify the specific trouble codes and address any underlying problems. Ignoring this light could lead to more significant issues and potential damage to the vehicle.