Harry Gibson on January 5, 2023 No Comments
Have you noticed the check engine light on the dash? You’ve done your diagnostics and determined that you have the code P0443? Well, if that is the case, then you are at the right place because there will be a lot to cover when it comes to this problem.
- Car Diagnostics
- The Problem
- EVAP System?
- Purge Solenoid?
- Causes
- Symptoms
- Diagnosing
- Replacement
- Conclusion
- F.A.Q
Having a problem like this can be a real pain to deal with. Vacuum leaks are a real nightmare because you don’t know from where they could come and to find them is really difficult for those who are not trained to do this work.
This is why you need to improve your troubleshooting skills and understand more about these types of codes that are often known to pop up and ruin your day. Frankly, no one wants to see the check engine light on the dash and I guess neither do you. That’s why we are going to help you out diagnose this problem quickly and effectively on basically any type of vehicle. That’s right, the solution for this will work on any car out there.
First, we will dive deeper and understand more about car diagnostics. Then we will elaborate more on the problem with the P0443 code and learn the definition. After that, we will learn how the EVAP system works as well as the purge control valve.
Then we will discuss the causes for this problem with the P0443 as well as the symptoms that this code gives to you. And after this, we will learn how to diagnose the problem and test this EVAP canister purge valve and if we determine that it is bad, how to replace it. And you don’t want to miss that.
Introduction To Diagnostics And P0443 Code
Now before we discuss the P0443 code and learn more about the causes and the possible symptoms, let’s first introduce ourselves to car diagnostics. I bet that there are a few people who are reading this that are not that familiar with how this diagnostics process is done to a car and we need to cover some of the basics first. If you want you can jump to the next chapter where we elaborate on the problem, if not, follow us.
When it comes to car diagnostics it is worth noting that modern cars are really complex. And diagnosing problems with modern cars is like you are sorting out a puzzle. Nothing is straightforward and everything is confusing.
For this, you will need to think logically. Like in this case, you need to start from the basics and learn how the EVAP system works on a car and how it affects other systems in a car. Once you are able to do that, you will be able to diagnose the issue.
And for this, learning all of the causes and symptoms of every code that you get will be a bonus. So, that’s the number one thing.
The second thing is to know how to use an OBD2 scanner. These scanners can be really simple on the low end and really complex on the high end. And you as a beginner need something simple or something in the middle and move on from there.
You might not get real-time readings with the basic scanners. But you will still get access to the codes like in our case with the P0443 code.
Now we can move on to learn more about this code and what it represents. So, follow us in the next chapter.
Evaporative Emission System Purge Control Valve Circuit
Now as we covered the basics, we can move on to learn the P0443 meaning. What does this code mean for you?
Well, this code is closely connected to the EVAP system that we are going to explain in the next chapter. What is important for you is that this system is an emissions system that is helping your car reduce its emissions.
What is bad though, it sometimes can malfunction and cause you a problem like in our case with the P0443 code.
The definition for this code is “Evaporative Emission System Purge Control Valve Circuit”. This means that there is a short in the electrical circuit of this valve.
This could be caused by a number of things but more on that we are going to cover later on in the article.
What is important for you is that you should not panic. This is not something that serious. But still, you need to sort out the problem and remove the check engine light from the dash. Sorting this problem out will help you overcome this obstacle.
And this code is really beginner-friendly oriented. Meaning that it is rather easy to diagnose in comparison to other EVAP codes. But before we diagnose the problem. Let’s learn how the EVAP system works in practice and then we will cover how the purge control valve works. And you don’t want to miss that.
How Does The EVAP System Work?
Now before we cover the possible causes for the P0443 code and how the EVAP canister purge valve works, let’s separate some time and learn more about how the EVAP system works in general. Knowing this stuff will be extra essential when it comes to understanding this problem. So, let’s begin.
Now let’s start with a history lesson before we dive into the complexities of this system. Namely, back in the 70s, there was an oil crisis here in the US. Prices of gas got crazy high and the gas guzzler cars had to be changed for something else that was smaller in displacement.
But that was not everything. There were also systems that were introduced and helped tackle some of the problems like the smog and other harmful particles that were released into the air.
And here the EVAP system comes into play. The EVAP is an acronym for Evaporative Emission System. So, what this system does in practice?
Well, this system has a simple role. And that is to collect the fumes that are created in the gas tank and to keep the gas tank pressurized all of the time.
As you probably know, fuel evaporates and there is a gas buildup in the fuel tank. These gases create really high emissions. So, the role of the EVAP is to redirect the fumes into a device known as a charcoal canister (aka the EVAP canister) and then from there to release the gases into the intake and then in the combustion to burn along with the gasoline.
It might be really complex to understand at first. But actually, it is really simple. The most important piece is the purge control valve and which we will cover next.
How Does The Purge Control Valve Work?
Now as we cleared how the EVAP system works. Let’s now understand how this purge valve works in practice.
First, to clear things out, this purge control valve is also known as an EVAP canister purge valve, or simply as a purge valve solenoid. We’ve discussed this before in our guide on the P0441 code.
This device is basically an electrical solenoid that activates once the conditions are met. And that is the pressure buildup in the EVAP system. In this case, the ECU also known as the car computer decides to activate the purge valve and release the pressure in the EVAP system. Simple as that.
This solenoid can fail though, it can get stuck in both open and closed positions. When the solenoid is closed, it will not allow gases to flow. And when it is stuck in an open position it will allow too much air to get into the intake and cause you a lot of troubles like a lean air to fuel mixture. With the P0171 or P0174 codes or something similar. For instance, the P0174 Chevy code.
You might also notice other similar codes, such as the P0171 Code Toyota or P0171 Nissan code. This is why it is really crucial for you to inspect the different codes that you will be getting along with the P0443 code. The more codes, the bigger the headache. But also the easier for you will be to locate the problem.
And as we noted the P0443 indicates a problem with this purge valve solenoid. But what precisely is the cause for this component to show such symptoms as the check engine light. Everything happens for a reason, right? That’s why in the following chapters we will elaborate on all of these possible cases and learn what could be the issue behind the problems with this solenoid.
Possible Causes For The P0443
Now as we cleared the basics of the EVAP system and learned how everything works, we can move up and start understanding the possible causes of this problem with the code P0443.
As we noted, this is very likely caused by a bad EVAP purge solenoid. But that isn’t always the case. So, in the following chapters, we will go through all of the possible causes of this situation.
1. Bad Purge Valve Solenoid
The first and most probable cause for the P0443 (or P0441 and the P0441 Dodge code) code is a bad purge valve solenoid. This is the component that activates whenever the ECM decides so. This valve basically purges the gases that have accumulated in the system and drives them into the engine.
Whenever this component fails. It could be stuck in a closed position and not allow anything to enter the combustion. Or to get stuck in an open position and allow a lot of gases to enter the combustion. Attributing to lean air to fuel mixture in the process.
This is why you need to troubleshoot this component and see if it opens and closes correctly if you want to sort out the problem. Later in the article, we are going to talk about that precisely in great detail. Now let’s move on to the next probable cause for the P0443.
2. Damaged Circuit Connector
The second probability is the connector for this purge valve solenoid. As you probably know, these components are exposed to a lot of stress during their long life.
The connections can get loose over time and also the connectors can also develop rust alongside them. So, when there is rust buildup in the connector and the connections are not clean, there is a high chance for the solenoid to malfunction and cause you a P0443 code that will indicate a problem with the circuit.
So, it is advised to unplug this solenoid and give it a good cleaning with a wire brush or sandpaper on the connectors. Clean them of the best you can and surely they will much make a lot better connection and possibly even sort out your problem. Now let’s move on to the next probable cause for the P0443 code.
3. Bad Wiring
The third probable cause for the P0443 can be bad wiring. As you probably know, wiring is essential if you want these components to work.
This sensor is constantly powered by the battery and when needed a signal is sent from the PCM to the solenoid that directs it to open.
So, these connections need to be really in good condition. If you park your car in a garage that has rodents, then it is likely that some of the wirings were eaten by these rodents and this is causing a short in the circuit.
Everything is possible. Even though the chance of this is relatively low, it is still a possibility to happen. You need to be prepared for all possible scenarios when it comes to issues like these. Now let’s move on to the last possibility.
4. Bad PCM/ECM
The last probability that we would like to cover when it comes to the P0443 code is the problem with the PCM itself. You might also notice other codes such as the P0603 code or the P2509 code.
The PCM as we mentioned is the main computer and sometimes these computers can fail and cause problems like this with the check engine light and throw a ton of codes for no particular reason.
In these situations when everything seems right, it is worth swapping the PCM with another one just to see if you have a bad PCM or not. Now let’s move on to the symptoms.
Purge Valve Symptoms
Now as we covered the probable causes for the P0443 code, we can move on and cover the purge valve symptoms.
As you probably know, when the purge valve fails it starts to make purge valve symptoms. That’s why we need to cover them as well. They will help you determine if this component is really faulty.
1. Check Engine Light
The check engine light will probably be one of the first purge valve symptoms that you will notice whenever you have a P0443 problem on your car. You are probably aware of this since you diagnosed it.
But there could be also other codes that could really help you out. Namely, codes concerning lean air to fuel mixture. Like a P0171 or P0174 (such as the P0171 Toyota code). Lean air to fuel mixture will be present whenever there is a purge valve stuck open.
2. Rough Idle
In addition to the lean air to fuel mixture along with the other purge valve, symptoms will be the rough idle. The engine will idle poorly when you have a situation like this.
The RPM needle will fluctuate and the car will not be happy at all under these circumstances with the code P0443 and the purge valve solenoid faulty. Now let’s move on to the next symptom.
3. Poor Fuel Economy
There will also be a poor fuel economy among the other bad purge valve symptoms. So, why is this the case?
Well, let’s say that the purge valve is stuck open. There will be a lot of unmetered air that will enter the system. Meaning lean air to fuel mixture.
So, the computer which is the PCM will try to adjust the ratio by dumping more fuel into the mix. And this means more fuel burnt and more money spent on gas. Your fuel economy will drop significantly with the P0443 code.
4. High Pressure Released When You Remove The Gas Cap
The last in our list of purge valve symptoms that we are going to cover are the fumes that will be present when you release the gas cap.
Also, if the valve is stuck in a closed position, there will be big pressure on the gas cap. And when you remove the cap, you will feel it. This is a clear sign that the purge valve is not doing its work and is not releasing the gases into the intake. That’s why you need to move on to diagnosing the problem. And how you can do that we are going to cover in the next chapter.
How To Diagnose The P0443 Code
So, we came to the important bit. And that is the diagnosing process of the purge valve solenoid to determine if this is the root cause of the P0443 code that is troubling you all this time. But how you can do this? Well, the short answer is by using a multimeter.
Having a multimeter in these situations is a real lifesaver. When it comes to electrical components, there is no replacement for this testing tool.
With this tool, you will be able to measure continuity and voltage. Two essential aspects when it comes to checking this solenoid.
Precisely, in this case, you will need to check if this component has continuity. Or in other words, if the electrical circuit is complete. This is the simplest way you can test this device.
Just turn the tool to read resistance and put the probes on the contacts. If it makes a beeping sound it means that the circuit is complete and the purge valve solenoid is working. If it doesn’t beep, it means that the solenoid is not in good condition.
You can also try to use a vacuum tester. For this, you will need to create a vacuum in the solenoid and then power the solenoid with 12V of power. Whenever there is too much vacuum, the solenoid should turn on automatically. If it doesn’t then it is probably faulty. How this is done you can check in the video that we attached above.
Purge Valve Replacement
Now as we covered how you can diagnose the purge valve and sort the P0443 code, we can now move to other topics. Namely, the purge valve replacement.
For this, you will need a new purge valve from the parts store. Just make sure that is the right part that you need. Anything else will not work for you.
This purge valve is usually located in the engine bay. But in some applications, it can be found in the rear end, next to the fuel tank.
Replacing it is really easy. Just remove the hoses and the connector, then plug the new component in and you are good to go. Simple as that. Why pay a ton of money for something this simple.
It is also cheap to purchase. You can find these solenoids for $30 to $50. So, sometimes it is better to replace it right away than to test it.
Conclusion For P0443 Code
In this article, we have covered quite a bit when it comes to the P0443 code. We learned what is this code and how the EVAP system works. This is essential because in most cases, this code is caused by the EVAP purge solenoid.
Then we have covered the symptoms that are associated with this code and how you can diagnose and sort out the issue quickly and effectively.
F.A.Q FOr P0443 Code
Now let’s answer some frequently asked questions.
What Are The Symptoms Of A Bad Purge Valve
The symptoms include the check engine light, frequent misfires, and rough engine idle. In addition to this, there could be increased pressure in the gas tank if the purge valve is stuck close.
How Do I Fix Code P0443
Fixing this code can be tricky because you need to determine first if the purge valve is good. If the purge valve is faulty, you can just go ahead and replace it with a new one.
How To Fix P0443 Code
Fixing this code really depends on the diagnosis, whether the purge valve solenoid is bad or the wiring connections are rusted. If the connector is bad and rusted, just clean it off with sandpaper. Or in case the solenoid is broken, replace it with a new unit.
P0443 Chevy
This code means that you have a problem with your EVAP system. More precisely with the EVAP purge solenoid. You need to troubleshoot this component to determine if it’s causing this issue. If it does, just replace it.
