The vapor pressure of a liquid is the point at which equilibrium pressure is reached, in a closed container, between molecules leaving the liquid and going into the gaseous phase and molecules leaving the gaseous phase and entering the liquid phase.n explanation of vapor pressure. Vapor pressure is constant when there is an equilibrium of water molecules moving between the liquid phase and the gaseous phase, in a closed container.
When a potential problem is detected, a dashboard warning light called a malfunction indicator light (MIL) is illuminated to alert the driver. An OBD system detects a problem well before symptoms such as poor performance, high emissions or poor fuel economy are recognized by the driver.
If you're like most car owners, you have little idea about what that light is trying to tell you or exactly how you should react. Call it the most misunderstood indicator on your dashboard, the check engine light can mean many different things, from a loose gas cap to a seriously misfiring engine. It doesn't mean you have to pull the car over to the side of the road and call a tow truck.