What can cause a vehicle to fail the Exhaust Emission System inspection?

The reason a vehicle may fail the Exhaust Emission System inspection due to disconnection of the EES is that it directly impacts the vehicle's ability to control and reduce exhaust emissions. The Exhaust Emission System is crucial for managing the harmful pollutants that vehicles release into the environment. If this system is disconnected or malfunctioning, it means that the emissions may not be processed correctly, resulting in higher levels of pollutants being emitted.

In contrast, while replacing the air filter, having under-inflated tires, or a non-functioning radio can affect vehicle performance or safety, they do not directly influence the outcome of an Exhaust Emission System inspection. The air filter is related to air intake and engine efficiency rather than exhaust emissions. Incorrect tire pressure may affect vehicle handling and fuel economy, but it does not play a role in the emission control systems. Similarly, the functionality of the radio does not bear any relevance to emissions and would not be a consideration in this type of inspection.