Here are 6 Signs You Have A Bad Charcoal Container (& How to Replace It)

The charcoal canister is also called EVAP canister. You probably heard it before, but didn't really take the time to understand what it was.

The failure of the charcoal canister is rare and is usually hidden underneath the vehicle. It's not uncommon for it to get forgotten.

How much does it cost and what happens to the strange component? Let’s take a look at the common signs to look for:

A check engine light is the most obvious sign of a poor charcoal canister. It may be difficult for you to refill the tank of your fuel at the station. When you open the fuel tank cap, there is a clicking sound.

Below is a list that explains the symptoms most commonly associated with a poor charcoal canister.

Bad Charcoal Vapor Canister Symptoms

1. Turn on the engine light

Your engine control unit monitors all the sensors within your car's engine and will save a trouble code. If one of these fails it will display a warning light and show you a dashboard check engine light to let you know that it is.

If the charcoal container has become contaminated, this is what could happen. The EVAP is a closed system and must hold a particular pressure. If the engine control unit notice that there is a leak in the system or if it is clogged – the check engine light will show up.

You will need a scanner that can check for trouble codes to find out why your check engine light flashes.

2. Problems with Filling Up The Fuel Tank

The fuel fumes are going through the charcoal canister, and if the canister is clogged – the fumes will struggle to pass, and it will create high pressure in the fuel tank.

This is also true when you refill your vehicle. The tank holds fuel, so the gas and air need to be emitted.

If the charcoal canister or fuel vapor vent line is clogged, the air will not be able to flow out when you pour fuel in – and this will cause the fuel hose nozzle to shut off, and it can even cause the fuel to pour out everywhere except in the fuel tank.

3. Hearing noise when fuel tank cap is opened

Similar to the previous reason, the charcoal canister will clog, creating a greater fuel tank overpressure than normal.

When you get close to filling up your vehicle with fuel, you will notice a lot more air coming out and in the tank. It creates an unpleasant hissing sound.

A little bit of under or overpressure in your fuel tank is fine – but if it seems to be a lot more than usual, you do probably have a problem with the EVAP system.

4. The Fuel Smell Odor

A split body in a Charcoal Canister can result in the canister losing its fuel vapor. A damaged canister canister can result in the vapor getting released into the air instead of being contained within the canister and being sent via the vent pipe or the purge valve.

The fuel vapor is strong-smelling and can be detected when it is turned on or running.

If you’re noticing a strong fuel smell from your vehicle, even when it’s not running, then your Charcoal Canister is a good place to start in the diagnostic process.

5. Failure Emissions Test

You must pass yearly emissions tests in many countries or states to have your vehicle legal for use on the roads. During this test, your vehicle’s emission levels are checked to ensure that the fumes that exit the exhaust are meeting regulations.

A faulty fuel canister could cause misfuelling and your vehicle may fail to pass its emission test.

It can be hard to locate this fuel canister as it tends to only work passively. You can try blanking off the fuel canister’s vent pipe and see if doing this affects your vehicle’s emissions. You should replace the fuel canister if it is faulty to ensure your vehicle meets emission standards.

6. Exhaust: Excessive smoke 

Your vehicle's faults can cause your engine to misfuel. If your exhaust is faulty, it will emit different colors of smoke. Your engine could be misfuelled if your exhaust starts smoking excessively.

This misfueling could be a result of your Charcoal Canister not operating as it’s designed to. Although it’s uncommon for a Charcoal Canister to be causing excessive smoke, it would be wrong to say that it never happens!

It is easy to test the exhaust pipe by removing it from the Charcoal canister. If the smoke does not change, you should try this. If the exhaust smoke changes, this could also indicate that there is a problem in your canister.

A Charcoal Canister's Function

Charcoal Canisters or Vapor Canisters absorb the byproducts of fuel from your tank. Instead of these fumes being vented out into the atmosphere – which isn’t very eco-friendly – they’re absorbed by your Charcoal Canister. Your fuel vapor is absorbed by the charcoal canister, which has an extra absorbent feature.

This vapor will build up over time and eventually it will need to be released. This released vapor gets pushed through the canister’s vent line and purge valve into the engine, where the vapor gets burnt off.

Charcoal Canister Locator 

The charcoal canister (or vaporcanister) is located usually under the vehicle. It's often right next to the fuel pump. Sometimes it's hidden beneath plastic covers so it's difficult to find. You may also find it in the engine bay on European vehicles.

Locations of the Charcoal Canister can be very different depending on what vehicle you have.

It’s worth noting that I’ve found these canisters in wheel arches on some of the European brands.

If you’re struggling to find it, your local dealership should be able to supply you with a component location.

Charcoal Canisters Replacement Cost 

The average cost to replace a charcoal canister depends on what model of car it is. The cost of a charcoal vaporizer canister is between $80 and $150 Labor costs between $50 and $150

Your chances of having your fuel tank replaced is slim. However, it can happen with high-mileage cars.

The charcoal container itself can be quite inexpensive, often selling for as low as 100 dollars.

It is usually quite simple to replace and can often be done with basic knowledge in under an hour. You should check that it is not too damaged on certain cars before you replace it.