Which factor can lead to a 'false pass' during a Smog Check?

A 'false pass' during a Smog Check occurs when a vehicle is passed despite having emissions problems that should have caused it to fail. One significant factor that can lead to this misleading outcome is malfunctioning or tampered emissions components.

When emissions components are not operating correctly or have been tampered with, they may not accurately represent the true emissions levels of the vehicle. For example, if a vehicle’s catalytic converter is damaged or removed, it might still pass the Smog Check if the inspecting equipment is unable to detect the issue due to modifications or improper functioning of the testing devices. This can create a situation where the vehicle is inaccurately assessed as meeting emissions standards, leading to a false pass.

Other factors, such as properly functioning emissions components or regular maintenance, would generally aid in ensuring a vehicle meets emissions standards. Using high-octane fuel is unrelated to emissions testing results in this context, as fuel type does not significantly impact emissions system performance for the purposes of the Smog Check.