Under what circumstances may a technician reject a vehicle for smog inspection?

A technician may reject a vehicle for smog inspection under various circumstances that would prevent accurate assessment of the vehicle's emissions or indicate that the vehicle is inappropriately equipped or functioning poorly. In the context of the provided question, each of these conditions points to significant issues with the vehicle’s ability to comply with emissions standards.

When a vehicle has visible smoke, it indicates that the engine is burning excessive fuel or oil, which suggests that the vehicle is likely emitting pollutants above acceptable levels. This can reflect a serious problem with the vehicle’s internal mechanisms and is a clear reason for rejection during the smog inspection.

If a vehicle is overheating, it signals potential mechanical failures that could also affect emissions. Overheating can lead to incomplete combustion, resulting in higher emissions. A vehicle that is overheating cannot be reliably tested for emissions, as the heat can alter the behavior of exhaust components, causing skewed results.

Non-disengageable traction control systems can complicate the emissions testing process, especially if they interfere with the normal operation and testing of the vehicle during the inspection. If a vehicle is equipped with such technology that cannot be disengaged, it may prevent the technician from performing the required tests accurately.

Thus, the correct answer encompasses the overall possibility of rejecting