Five Signs That Your Canister Purge Valve Is Not Working (& Their Replacement Cost)

While the average driver doesn’t have a clue about what goes into their vehicle’s emission systems, there’s a lot of new components that have entirely overhauled how modern engines run.

The EVAP technology is an example of such innovative technologies. There are many parts that work together to make the EVAP systems function. However, the vaporcanister purge valve is one of the key components to the EVAP System.

When everything is working correctly, it’s a great component that significantly reduces emissions. But when it’s not, you can notice an array of problems. Below we’ll break down everything you need to know about this newer technology that makes its way onto vehicles.

The symptoms and function of the purge valve will be examined, as well as the cost to replace it. Let's start by looking at some of the symptoms.

Five Bad Canister Purge Vave Symptoms

The most common symptom of a bad canister purge valve is a check engine light on your car’s dashboard. Most cases will not cause any additional problems.

A bad canister purge device is characterized by the following symptoms:

While the vapor canister purge valve solenoid is an emissions component, that doesn’t mean you won’t notice a few performance issues if you don’t fix it right away.

Here is a list that explains the most frequent symptoms associated with a defective canister purge device.

Make sure your engine light is on

The most common thing you’ll notice from a bad vapor canister purge valve is that you’ll get a check engine light that you weren’t expecting. While the symptoms can change depending on whether or not the valve is stuck open or closed, one thing that shouldn’t change is that you should get a check engine light.

Creeping Emissions

If the vapor canister purge valve is stuck closed instead of open, the valve won’t push any fuel vapors back into the engine. Instead, they’ll run straight out of the exhaust, which will cause much higher emission levels.

Of course, you probably won’t notice this unless you take your vehicle in for an emission test.

Poor Engine Performance

When the vapor canister purge valve is stuck open, you’re getting more air in the system than your vehicle expects. That means every time you hit the throttle; your vehicle isn’t dropping enough fuel in the engine for the amount of fuel there.

While these effects will be more noticeable at lower RPMs, they can affect performance across all engine speeds; it just isn’t as noticeable.

Related: 8 Causes Why Your Car Won’t Accelerate

Very difficult to begin

The vapor canister purge valve does a lot of its work when you’re starting up your vehicle to empty the fuel tank of gases, so it makes sense that this would be when you would notice most of the symptoms.

If the purge valve is stuck open, you’re going to have an excess amount of air when you go to start the engine, and since your vehicle isn’t accounting for this, it’s going to throw off the fuel to air ratio.

While your vehicle should still start, you’re going to notice that it takes a bit more work to get there. This valve will rarely cause your vehicle to stop starting.

Rough Idle

The vacuum canister purge valves of the vacuum canister run on vacuum. A vacuum leak can cause engine problems, particularly at low engine speeds.

Vacuum leaks on canister purge valves will result in an unpleasant idle. The severity of the problem will depend on how large it is.

Related: Rough Idle Causes & How to Fix it

Vapor Canister Purge Valve Function

Unless you’re a mechanic or an engineer, you’ve probably never heard of a canister purge valve before. To begin with, it’s an emissions component that redirects excess fuel vapors back into the engine.

The entire system that it’s a part of is your vehicle’s EVAP (Evaporative Emission) system. This works with the charcoal canister and captures excess fuel vapors to allow the engine to burn them again.

You can reduce your carbon emissions by using fuel vapors to burn instead of letting them out into the atmosphere. This maximizes the energy production and minimizes the harmful side effects.

Because it’s effective at reducing the overall amount of harmful emissions, many auto manufacturers have started to implement them into new vehicles to meet rising emission standards.

If the valve for the vapor canister purge is stuck open, it will allow too much air to enter the system. This causes performance problems. If it becomes stuck closed, you will see a dramatic increase in your emission levels.

Vapor Canister Purge Valve Location

Two locations are possible for the vapor canister purge hose valve depending on your vehicle.

The Canister purge controller valve can usually be found near the fuel tank. The fuel tank can also contain the Canister purge control valve.

The component won’t look like much. Typically, it’s nothing more than a little black plastic component with an electrical connector and a vacuum line on each end. While it can be hard to identify, it’s usually pretty easy to access once you’ve found it.

Vapor Canister Purge Valve Replacement Cost

An average cost to replace a vapor canister purge valve is $50-$300, depending on your car and labor costs.

While those little plastic components might not look like much, they’re not cheap to replace. The part alone usually costs between $30 and $150. You must also consider labor costs.

This cost can vary depending on the vapor canister purge valve’s location and how hard it is to reach, but the cost usually ranges between $20 and $150.

If you are looking to do the work yourself, it’s pretty straightforward to replace a vapor canister purge valve that’s in the engine bay. To complete the task, you will need to locate and possibly remove the intake cover.

If the valve is attached to the fuel tank’s rear, you’ll likely need to jack up the rear end of the vehicle and remove the tire to gain access to the area. While this isn’t a ton of work if you have the proper equipment, it certainly can slow down the process a bit.

But considering that these simple steps can save you between $50 and $150, it’s typically well worth the few extra steps! For the final step, make sure to reset your engine code.

FAQs about Purge Control Valve