What is a purge valve on a car?

A purge valve is a component of a car's emissions control system that is responsible for managing the flow of fuel vapor from the fuel tank to the engine intake manifold. The valve is typically located near the fuel tank and is controlled by the car's engine control module (ECM) or powertrain control module (PCM).

The purpose of the purge valve is to allow the engine to burn fuel vapor that has accumulated in the fuel tank, instead of releasing it into the atmosphere as harmful emissions. When the engine is running, the ECM or PCM opens the purge valve to allow the fuel vapor to be drawn into the intake manifold to be burned along with the regular air-fuel mixture.

If the purge valve becomes faulty or clogged, it can lead to issues such as rough idling, decreased fuel efficiency, and increased emissions. Common signs of a bad purge valve include the check engine light coming on, a hissing sound coming from the engine, and difficulty starting the car.

It is important to have a malfunctioning purge valve diagnosed and repaired by a professional mechanic to ensure that the vehicle continues to run efficiently and meet emissions standards.