ASE Auto Maintenance and Light Repair Certification (G1) Practice Test

A malfunctioning PCV (Positive Crankcase Ventilation) valve can lead to several engine problems, primarily oil leaks and increased emissions. The PCV valve is responsible for regulating the flow of crankcase gases back into the intake manifold to be burned in the combustion process, which helps maintain optimal engine performance and reduce harmful emissions.

When the PCV valve is stuck open or closed, it can disrupt the proper flow of these gases. If the valve is stuck open, it can allow excessive amounts of air into the crankcase, causing the engine to operate inefficiently, and potentially leading to oil leaks due to increased pressure in the crankcase. On the other hand, if the valve is stuck closed, it can cause a build-up of gases within the crankcase, leading to increased pressure that can also result in oil leaks and increased emissions from the vehicle.

In this context, options like better throttle response, increased fuel efficiency, or reduced engine noise are not directly related to the functioning of the PCV valve. Instead, a functioning PCV system is crucial for maintaining environmental standards and the overall health of the engine, which is why identifying issues with the PCV valve is significant for effective vehicle maintenance and repair.