What is EVAP Canister its Function, Symptoms and Replacement Costs

Summary 

The EVAP canister is a rectangular plastic container filled with activated charcoal to absorb and store gasoline vapors. It is located somewhere in the vehicle and connected to the fuel tank through the tank vent line.

EVAP canisters are also referred to as vapor canisters or charcoal canisters. 

When the engine is driven, the PCM opens the canister purge valve to draw the vapors into the engine using an intake vacuum.

The function of an EVAP system is to stop fuel system fumes from leaking directly into the atmosphere. Vent lines from the fuel tank pass vapors to the vapor canister, where they are trapped and stored until the engine is started.

The EVAP canister in a vehicle is an important part of the emissions control system, capturing and storing fuel vapors to prevent them from escaping.

A clogged or malfunctioning EVAP canister can cause poor engine performance, increased emissions, and a check engine light. A bad vapor canister is one of the reasons why your car fails an emission test.

Now, let’s go deep into explaining EVAP Canister!

Contents

What is an EVAP canister?

An EVAP canister is a rectangular plastic container filled with activated charcoal to absorb and store gasoline vapors. It is located somewhere in the vehicle and connected to the fuel tank through the tank vent line.

The canister is filled with fuel vapor from the car’s engine, which is drawn back into the engine to be burned. This process is known as “purging.” A purge valve is used to achieve the operation.

The evaporative emission control canister is a small container mounted inside a panel or in the corner of the engine bay.

This small canister is filled with activated charcoal that absorbs harmful fuel vapors. These vapors are stored in the canister until the engine is hot.

EVAP Canister Diagram

The EVAP system prevents gasoline vapors from escaping into the atmosphere by using a fuel tank, charcoal-filled vapor storage canister, valves, hoses, and a sealed gas cap.

It traps fuel system fumes in the canister until the engine is started, then allows them to be drawn into the intake manifold and burned in the engine.

 

Evaporative Emission Control System

How To Fix a Clogged or Bad EVAP Canister

The EVAP canister in a vehicle is an important part of the emissions control system, capturing and storing fuel vapors to prevent them from escaping.

A clogged or malfunctioning canister can cause poor engine performance, increased emissions, and a check engine light. It’s important to follow the manufacturer’s recommendations and consult a professional mechanic if unsure about diagnosing or fixing a clogged EVAP canister.

Regular maintenance and inspection can help prevent future issues.

Read full article on the symptoms of a bad EVAP canister.

How To Test EVAP Canister

  • Visual Inspection: Check the charcoal canister for any physical damage, such as cracks, broken ports, etc.
  • Check for contamination: remove the canister and check for liquid fuel inside the canister, if liquid fuel is found, the canister needs replacement.
  • Check air flow. Check that the canister is not clogged and that air can flow through it easily.

How Much Does a Vapor Canister Replacement Cost?

Replacing a faulty vapor canister can set you back by anywhere between $35 and $990 on parts alone. Labor costs are estimated between $90 and $115. There can also be additional costs, like taxes and fees, that you have to account for because of your vehicle and location.

 

That is all for this article where EVAP canister are being explained. I hope it wa helpful if so, kindly share with others. Thanks for reading, see you around!

Scroll to Top