During the tailpipe emissions inspection, if the MIL light activates, what is the correct procedure?

When conducting a tailpipe emissions inspection, the activation of the Malfunction Indicator Light (MIL) indicates that there's a potential issue with the vehicle's emission control system. The correct procedure in this scenario is to enter "pass" during the MIL functional test if the light operates correctly, which means the light illuminates when the ignition is turned on and goes off when the engine starts, indicating that the onboard diagnostics system is functioning normally.

This procedure is important because the purpose of the functional test is to verify that the MIL is operating correctly. If the light is not illuminated when expected, it may suggest a failure in the vehicle’s onboard diagnostics system that could affect emissions controls. Merely passing the vehicle without checking the MIL's functionality defeats the purpose of ensuring that the vehicle complies with emissions regulations.

Other options, such as immediately failing the vehicle or ignoring the MIL light, would not follow the established protocols for inspection and could lead to overlooking potential issues that may compromise air quality. Resetting the MIL light and retesting could also mislead the inspector regarding the vehicle’s compliance status without addressing the underlying problem. Hence, confirming proper MIL operation is pivotal in assessing the vehicle's emissions control readiness.