Since the early 1970s, all production vehicles have been fitted with an evaporative emission control (EVAP) system. The technology prevents harmful fuel vapors from entering the atmosphere by trapping then purging the vapors.
One of the primary components within the EVAP system is the canister purge valve (often referred to as the canister purge valve solenoid on modern vehicles). Although the purge valve is designed to last the life of the vehicle, that doesn’t always happen. If the purge valve fails, your car will likely exhibit one or more noticeable symptoms.
To better understand the purge valve, it helps to know how the EVAP system works. As was mentioned, the EVAP system prevents fuel vapors from entering the atmosphere. The system does this by trapping the vapors in a charcoal canister, then “purging” the vapors into the engine when conditions are correct.
When the engine is off, fuel vapors from the gas tank are stored in the canister. The canister contains activated charcoal, which traps the vapors until the engine is running and conditions are correct for a vapor purge.
Normally, the charcoal canister is open to the atmosphere to allow fresh air to enter. But on modern vehicles, the engine computer, which is often referred to as the powertrain control module (PCM), closes the charcoal canister when testing the integrity of the EVAP system. The PCM operates a vent valve solenoid to open and close the canister.
The PCM also determines when to initiate a canister purge. When the module deems conditions are correct, it commands a solenoid to open the purge valve. The solenoid is typically integrated with the valve, which is why the valve is often referred to as a canister purge valve solenoid.
Opening the purge valve creates a vacuum that pulls fresh air through the vapor canister. The fresh air picks up the fuel vapors and delivers them to the engine’s intake manifold. From there, the vapors enter the engine to be burned during the normal combustion process.
Do you think you might be dealing with a faulty purge valve? If your vehicle is exhibiting one or more of the following symptoms, you might be correct.
Note: Because many other problems can present the same symptoms as a faulty purge valve, you’ll want to perform a thorough diagnosis before condemning the valve.
The PCM monitors purge flow, as well as the integrity of the purge valve solenoid and the solenoid’s circuit. If the module detects a problem with the purge valve, it turns on the check engine light and stores a corresponding diagnostic trouble code (DTC) in its memory.
A purge valve that is stuck open can cause fuel-saturated vapors and/or fresh air to be dumped into the intake manifold under the wrong conditions. As a result, the engine may exhibit performance problems, such as rough running and stalling.
It’s also possible for a stuck closed purge valve to cause driveability issues. The PCM may lean out the engine’s air-fuel mixture in anticipation of fuel vapors being delivered by the purge valve. If those vapors are absent—due to a stuck closed purge valve—the engine may exhibit performance problems (e.g., rough running and stalling).
If the purge valve is stuck open, vapors from the charcoal canister can sneak into the intake manifold during refueling, making the vehicle difficult to restart.
Although rather uncommon, a purge valve that is stuck completely open can cause the fuel tank to collapse or deform. The issue typically happens when the canister vent valve is closed, preventing fresh air from being drawn into the EVAP system.
When the purge valve is stuck wide open and the vent valve is closed, an excessive vacuum is created within the EVAP system. In some rare cases, the scenario causes the fuel tank to be sucked in and partially collapse. For example, there is a technical service bulletin (TSB) that describes such a problem on 2012-2014 Ford Focus models.
Your vehicle’s canister purge valve solenoid is essential to the EVAP system. Without it, the signals from the PCM might never make it to the rest of the system, meaning you’ll be stuck with the symptoms we’ve listed like engine performance problems and hard starts. Thankfully, finding a replacement canister purge valve solenoid is easy with CarParts.com.
CarParts.com offers a wide range of aftermarket parts at different price points to suit your budget. The website is easy to navigate and you’ll be able to place your order in a few easy clicks. Make sure to use our built-in vehicle selector to guarantee your chosen solenoid fits your vehicle’s make and model. If you have any questions, feel free to reach out to our friendly and helpful customer service team who will be happy to help around the clock.
Purchase your brand new canister purge valve solenoid at CarParts.com today.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
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Thank you for sharing info, had mine replaced, chevy dealership $350. Ouch.
2016 Honda civic 1.5 turbo every 3 weeks throw’s Emissions system problem code, smoked twice, once got whiff of smoke at cap less filler, replaced, code P0456 returned 3 weeks later, smoked at dealer found nothing, passed emissions got sticker, drove to maine, over 500 miles, all of october, threw code again, thinking of replacing purge valve, charcoal canister… others are saying cover engine on dash and drive it… 88,200 miles always ran premium fuel