How To Reset Check Engine Light After Replacing Purge Valve

How To Reset Check Engine Light After Replacing Purge Valve

The check engine light can cause anxiety for any car owner. It’s a mysterious signal that something might be wrong with our beloved vehicle, leaving us worried about costly repairs.

I will explain to you how the purge valve causes the check engine light to come on and how I reset it.

Here’s a step-by-step guide on how to reset check engine light after replacing purge valve.

Which Factors Cause the Check Engine Light?

Common Causes for Check Engine LightPossible Issues
Loose Gas CapLoose, damaged, or missing gas cap
Oxygen SensorFaulty oxygen sensor – Result in improper air-fuel mixture
Catalytic ConverterFailing catalytic converter – Reduce exhaust system efficiency
Mass Airflow Sensor (MAF)Dirty or faulty MAF sensor – Affect engine performance
Spark Plugs and Ignition CoilsWorn-out spark plugs or faulty ignition coils
EGR ValveMalfunctioning EGR valve – Impact emissions control
Fuel InjectorsClogged or faulty fuel injectors – Affects fuel delivery
Throttle Position Sensor (TPS)Defective TPS-causing improper throttle response
Exhaust Gas Recirculation (EGR) SystemIssues with EGR system components – Affects emissions
Vacuum LeaksLeaking vacuum hoses or intake manifold gasket leads to air leaks
Transmission IssuesProblems with transmission components – Result in improper shifting
Battery or Charging SystemFaulty battery or alternator affect electrical system performance
Evaporative Emission Control SystemProblems with EVAP system components, such as a faulty purge valve

What is the Duty of a Purge Valve?

The purge valve, also called the purge valve solenoid, is part of a car’s EVAP system. It has an important job. It is to regulate the movement of fuel vapor from the charcoal canister to the engine’s intake manifold.

What is the Charcoal Canister?

A charcoal canister is where fuel vapor gets burned. It contains special charcoal that can absorb and hold onto the fuel vapor. The EVAP system serves a crucial purpose: to prevent harmful fuel vapors from escaping into the air.

When the fuel in the tank evaporates, the vapor needs to be captured and stored temporarily. That’s where the charcoal canister comes in.

What Is the Need for the Purge Valve in Charcoal Canister?

Eventually, the stored fuel vapor must be released from the charcoal canister and burned in the engine’s combustion chambers. This is where the purge valve steps in. The purge valve solenoid is controlled electronically by the engine’s computer, called the engine control module (ECM).

When the ECM determines that the conditions are right for purging the stored fuel vapor, it activates the solenoid, causing it to open.

purge valve

What Happens When the Purge Valve Open?

When the purge valve opens, it allows the fuel vapor to flow from the charcoal canister into the intake manifold. There, it mixes with the incoming air and is burned during the combustion process. This ensures that unburned fuel vapors don’t escape into the atmosphere.

How does Purge Valve Cause Check Engine Light?

If the purge valve solenoid malfunctions, it can lead to various issues. For instance, if it gets stuck in an open position, it can create a vacuum leak.

This can cause problems like rough idle, lean conditions (too much air, not enough fuel), and hard starts, and may cause the check engine light and trigger trouble codes related to the EVAP system.

Moreover, when refueling, a faulty purge valve can allow an excessive amount of fuel vapor into the intake manifold, resulting in difficulties starting the vehicle and rough idling.

How To Reset Check Engine Light After Replacing Purge Valve

check engine light of car

It seems like you have already replaced the purge valve to address the issue causing the check engine light. Now, you are wondering how to reset the check engine light. So, how to reset the check engine light after replacing the purge valve? Here is how I did it:

Step 1: Turning off the Engine

First, I made sure the engine was completely turned off.

Step 2: Finding the OBD-II Port

I found the OBD-II port, which is usually hidden under the dashboard on the driver’s side.

Step 3: Using a Code Reader

For this task, I used a handheld code reader, a tool that helps diagnose car problems. I connected it securely to the OBD-II port to communicate with the car’s internal system.

Step 4: Powering on the Code Reader

I turned on the code reader and saw different options on the screen.

Step 5: Navigating the Menu

Then, I navigated through the code reader’s menu to find the main options.

Step 6: Clearing the Trouble Codes

I used the code reader to read and clear the diagnostic trouble codes (DTCs) stored in the car’s memory. These codes give information about the problems causing the check engine light to turn on.

Step 7: Confirming the Clearing Process

The code reader asked for confirmation before erasing the codes. I made sure the engine was off and gave the code reader permission to delete the stored codes.

Step 8: Disconnect the Reader

After successfully clearing the codes, I disconnected the code reader from the OBD-II port. It was a moment of accomplishment, like unplugging a device after finishing a task.

Step 9: Checking the Check Engine Light

I started the engine again and watched to see if the check engine light stayed off. Yes! It was gone.


What is the meaning of EVAP?

EVAP is the short form of the Evaporative Emission Control System.

What is the task of the evaporative emission control system?

The fuel system in your vehicle is a closed, sealed system specifically designed to prevent the escape of fuel vapors into the atmosphere. The Evaporative Emission Control System (EVAP) plays a crucial role in capturing and reusing unburned vaporized hydrocarbons. It functions by drawing in the fresh air and delivering them to the intake system for re-burning within the engine.

What controls the purge valve?

In recent vehicles, the engine computer regulates the purge valve. The purge valve is an electrically operated solenoid that is closed when the engine is not running.

Can a bad EVAP purge valve cause misfires?

Yes, a bad purge valve can cause misfires. When the purge valve is stuck open, it creates a vacuum problem. This may lead to a misfire. However, a purge valve is not always the primary cause of a misfire. To check if the purge valve is causing the problem, you can pinch off the rubber lines connected to it and observe if the car runs better.

Apart from the purge valve, a common culprit for the misfire is the fuel injectors. This happens when the fuel injectors get stuck open or stick open intermittently, which causes misfiring of the engine. You might also notice a fuel smell in the oil if this is the case.


I hope you understand how to reset check engine light after replacing purge valve. The purge valve, an essential component of the EVAP system, regulates the flow of fuel vapor from the charcoal canister to the engine’s intake manifold. Its malfunction can lead to vacuum leaks, various issues, and the check engine light.

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