An EVAP leak is a fault in the evaporative emission control system (EVAP) that is responsible for capturing and storing fuel vapors from the car’s fuel tank and burning them off in the combustion chamber when the engine is running. An EVAP leak occurs when these vapors escape from any part of the system, which can lead to a fuel odor or a check engine light. The most common causes of EVAP leaks include bad seals and O-rings, a failing purge valve, a damaged hose or vent, or a defective leak detection pump. It is important to identify and repair an EVAP leak as soon as possible, as it can lead to serious problems.

If you suspect that your car has an EVAP leak, you can check for a check engine light or use an OBD-II scanner to check for specific error codes related to the EVAP system. You can also take your car to a mechanic for a professional diagnosis. Once you have identified that you have an EVAP leak, it is important to fix it as soon as possible. Depending on the cause of the leak, it may be possible to make a temporary fix by replacing any worn-out parts or cleaning away any rust or corrosion on the system’s components. However, it is best to have a professional mechanic inspect and repair the EVAP system, as it is a complex system.

It is safe to drive with an EVAP leak, but you should get the leak repaired right away. Uncontrolled emissions from an EVAP leak account for about 20 percent of the pollution produced by vehicles, and fuel vapors are emitted from vehicles any time there is gasoline in the tank, even if you are not driving the vehicle. Three symptoms that will let you know that there is an issue with the EVAP system include a fuel odor, a check engine light, or a loose gas cap.