Which of the following is a reason newer vehicles might fail emissions testing?

Newer vehicles might fail emissions testing primarily due to unresolved emissions system issues. Even if a vehicle is relatively new, it can still develop problems within the emissions control systems, such as a malfunctioning catalytic converter or issues with the onboard diagnostics (OBD) system. These problems could lead to increased emissions of pollutants beyond the regulatory limits set by authorities.

While newer vehicles tend to be more fuel-efficient and designed with advanced emissions control technologies, any unresolved issues in these systems can cause them to underperform when it comes to emissions testing. This highlights the importance of regular maintenance and diagnostics checks, even for newer models, to ensure compliance with emissions standards.