What does it mean when the dashboard displays 'Please Check Emission System'?

[TuckerLee]

The dashboard displaying 'Please Check Emission System' indicates a potential issue with the exhaust pipe. The vehicle's exhaust pipe is equipped with a three-way catalytic converter designed to reduce the levels of pollutants in the exhaust gases. If the three-way catalytic converter fails, it can cause the vehicle's emissions to exceed the standard limits, resulting in the vehicle failing the annual inspection. The car's exhaust pipe, also known as the exhaust flexible pipe, is installed between the engine exhaust manifold and the muffler, providing a flexible connection for the entire exhaust system. It serves to reduce vibration and noise, facilitate installation, and extend the lifespan of the exhaust muffler system. The exhaust pipe is primarily used in light-duty vehicles, compact cars, and buses. Its structure consists of a double-layer corrugated pipe covered with a steel wire mesh sleeve, with clamping rings at both ends. To enhance the muffling effect, the corrugated pipe can be equipped with an expansion joint or mesh sleeve internally.