This article will give you a complete guideline on How to Test Purge Valve with Multimeter. From different ways of testing and cleaning to in-detail discussion about symptoms of damaged purge valve, this article is going to provide you with every necessary detail you need.
The purge valve is an indispensable part of your car’s Evaporative Emission Control System (EVAP). As the name suggests, it is associated with purging. It is a component of emission control of your vehicle. It locks the fuel system in our car so that the toxic vehicle fuel vapors do not get released into the environment or returned into the vehicle. The toxic fuel vapors from the fuel tank are sealed into a charcoal canister by the purge valve.
A purge valve, also known as a purge solenoid is electronically operated and connected with the engine. When an engine is ignited, the purge valve also gradually boots up. However, when the engine is turned off, it stops working completely.
A purge valve is a vehicle’s integral component of the EVAP system. A bad purge can cause severe issues like engine failure and choking. Therefore, it is essential to have knowledge about cleaning a purge valve to even diagnosing a bad purge valve. Also read- fluke 179 vs 87v
Table of Contents
How to Test VW Purge Valve – 3 Steps to Test the Purge Valve Through a Multimeter
So can you test a purge valve? The ways to test the purge valve through a multimeter may vary in different car models. Check the price of Klein Tools MM600 HVAC Multimeter
However, the basic steps are the same for all car models. To begin with, to test purge vales which are a part of EVAP system of a vehicle, the resistance between the terminals has to be checked. Below is a step-by-step basic guideline for testing the purge valve through a multimeter that applies to all car models.
#Step 1: Locating the Purge Valve
The first thing one has to do is locate where the purge valves of the vehicle are. But, before that, one must make sure that the engine has been switched off for a minimum of 15 minutes to half an hour. After making sure of that, you need to find the purge valve. Generally, they are placed behind the silencer and placed on top of it. What is behind the silencer is called EVAP charcoal canister. The purge valves are placed inside the canister. If you still have trouble finding the purge valves, the manual of your car can be a great help or you can also search the internet by specifying the model of your car with its engine graphics.
#Step 2: Rearranging the Cables
After finding the purge valves, you can notice a 2-pin harness that connects to the device. Now, you need to disconnect it and then connect it with the adapter cables of the multimeters. The adapter cables usually come with the testing kits of the multimeter. In short, the purge valve’s terminals should be connected with the multimeter’s cables.
#Step 3: Testing or Checking
In the last step, you need to measure the resistance. Any resistance lower than 22.0 ohms and higher than 30.0 ohms would indicate that you need to replace the valve. If you have an extra valve, you should replace it on the spot. But if you need to go to a shop, you must reconnect the harness cables to the device.
How to Clean Purge Solenoid Valve
Purge Solenoid valves can be clean in two different ways depending upon your technical knowledge and expertise. For most people, cleaning the dirt that hampers the functionality of a purge valve can be done by simply cleansing the internal components without actually opening them.
Cleaning Purge Solenoid Valve without Opening
#Step 1:
Spray a sufficient amount of carb cleaner or Mass Air Flow Sensor cleaner (MAF Cleaner) on both the tubes of your valve.
#Step 2:
After spraying, cover both ends of the tubes with your fingers and shake well. Wait for several minutes while keeping both ends covered. The cleaner will remove the dirt by then.
#Step 3:
After waiting several minutes uncover both ends of the tubes and let the liquid you sprayed drain out completely from the tubes. The drained liquid should be dark with dirt, charcoal, and debris. Repeat Step 1 and Step 2 as many times as you wish. Once you notice that the drained liquid looks clean and clear, this should suggest that your valve is completely cleaned.
#Step 4:
Spray contact cleaner in the switch of the car and the connector of the valves. After that, let everything dry completely.
Deep Cleaning your Purge Solenoid Valve by Opening It
One word of warning, do not proceed to deep clean your purge solenoid valve without proper technical knowledge. Anyway, you can manage to open a purge valve with the help of a screwdriver or a small knife.
#Step 1:
In most purge valves, the two halves are glued together. First, you have to remove as much glue as possible. After removing enough glue, try to tear both ends of the casing apart in a firm manner but with enough caution.
#Step 2:
After tearing the two halves apart, you will have a small cap-like rounded piece on one half and on the other one, you will find all the working parts such as the solenoid. Now, from the case, remove the body of the valve.
Source image: electricproblems.com
#Step 3:
In step 3, you have to check the condition of the rubber parts and the o-rings. If they are not broken, try lubricating them with silicone grease
#Step 4:
Spray the carb cleaner or MAF cleaner on the interior of the solenoid as shown in the picture below:
It is a good idea to rub the openings with the help of a dry cloth if you want a deep cleaning.
#Step 5:
After the cleaning is done, the case should be resealed with glue or rubber. Before sealing the valve with glue or robber, make sure you have reassembled everything together properly. Because it can be very difficult to reopen the two halves of a sealed valve. After sealing the valve, let the glue or robber dry.
How to Test GM Purge Solenoid
The best place to look up how to test GM purge solenoid is the vehicle’s manual. The internet is another option.
Purge Canister Valve Problem
The purge valve is an integral component of a vehicle’s Evaporative Emission Control System (EVAP). So, problems or issues with the purge canister valve would cause a wide range of issues with the EVAP system. The most repeated problem or issue that occurs with a purge valve is when it doesn’t fully get closed. As a result of a problematic purge valve, the output level of the engine’s emissions gets hampered, even engine failure is possible. The Purge valve canister can cause problems if it is clogged with dust and dirt. Sometimes, extreme weather conditions can lead to purge canister valve problems.
Purge Valve Ticking
The purge valve makes a ticking or clicking noise when the car is running. But the noise is ideally cannot be heard from inside the car. However, if the ticking noise is too harsh or loud or it can be heard from inside the car, there’s a good sign there are some issues with your purge solenoid valve.
What Happens When a Purge Valve Goes Bad
What happens if purge valve is stuck closed? As mentioned above, if a purge valve goes bad, it causes a wide range of issues with the EVAP system of a car. The engine’s output level of emission is highly affected by a bad purge valve. However, the good thing is, a purge valve always gives various indications when it goes bad. Some of the symptoms of a bad purge valve are discussed for you below:
Check Engine Light On
The check engine light on your dashboard lights up for various problems in your vehicle and a bad purge valve is one of them. The purge valve is controlled by the engine. So, when the purge valve fails, the check engine light is turned on. When there is a higher or lower level of vapors detected by your vehicle the check engine warning is set off. Also, a variety of EVAP system error codes are displayed, e.g.: P0446, P0441, etc.
Rough Idling and Other Engine Problems
When the canister purge valve in your vehicle has a problem, i.e., it sticks open or does not close completely, your car engine will have a rough idle. Because when the purge valve does not close completely, it results in a vacuum leak which badly hampers the idle speed and quality of your vehicle’s engine. A broken purge valve or the hoses attached to the purge valve can also create a vacuum leak. If your car has a rough idle, your vehicle will not accelerate in a smooth and consistent manner, particularly when you are driving at a low speed.
Difficulties in Starting the Car
When the canister purge valve in your car is stuck open or not close fully, the resulting vacuum leak will create problems while starting your car. The outside air that enters the engine because of the leak will disrupt the internal combustion process of the engine. This may cause the engine not to start.
The Decrease in Gas Mileage
The EVAP system depends majorly on the state of the canister purge valve of your car. So, when the EVAP system does not work soundly because of a bad purge valve, it affects the mileage. The gas is not stored in a bad purge valve, rather it is leaked into the environment. This causes mileage to be significantly lower than usual.
Failing the Emission Test
The canister purge valve takes the responsibility of redirecting the fuel vapors back into the engine. This stops the toxic hydrocarbons and other fumes from spreading into the environment. A failed or bad canister purge valve would cause your vehicle’s tailpipe to emit these toxic fumes into the environment. So, your car will also fail the emission test.
Damaged Gaskets and Oil Leakage
There will be a pressure that is continuously increasing because of a malfunctioning purge valve, as the vapors will not be emitted. If the pressure keeps building up for a long period, it may become so intense that it could destroy the rubber seals and gaskets. When these are ruined, as a consequence there will be oil leakage. Oil would leak from the emission system to the engine, causing serious damage to your engine.
Driving with a bad purge valve- What happen
The purge valve is a fundamental element of a vehicle’s Evaporative Emission Control System (EVAP). Driving with a bad purge valve can harm your engine’s health. It also results in environmental pollution as the toxic fumes are discharged into the environment. Furthermore, the mileage you get is also significantly lower in the case of driving with a bad purge valve.
What are the symptoms of a bad purge valve?
- Rough idle. The first symptom is a rough idle.
- Difficulty Mostly associated with a bad canister purge solenoid is difficult starting.
- Check Engine Light comes on. A defective canister purge solenoid set off the Check Engine Light.
Can a Bad Purge Valve Cause Misfire?
A bad purge valve can lead to ser predicaments such as causing a misfire. A bad purge valve doesn’t close fully or doesn’t open in time. As a result, an excessive amount of fuel vapor starts gathering in the charcoal canister. If things continue like this for a longer period, the engine cylinder is engulfed with fuel vapors that get repeatedly created and burned. These burning vapors can lead to a fire break out in the engine and the engine may choke.
Frequently Asked Questions
How do you test a purge valve?
A canister purge valve can be tested in different ways such as by using a battery and vacuum pump or by using a multimeter. With a multimeter, you need to measure the resistance of the purge valve. On the other hand, by using a vacuum pump, you need to exert vacuum into the canister valve.
How do I know if my purge valve is bad?
There are some definitive symptoms your vehicle is going to exhibit when the purge valve is bad. The most common signs for a bad purge valve are listed below: ● Lower Gas Mileage ● Emission Test Fail ● Check Engine Warning ● Rough Idling ● Car Starting Difficulty ● Damage Gaskets
What happens if purge valve is stuck closed?
When a purge canister is stuck closed it will prevent the EVAP system from combusting the toxic fumes inside the engine. Instead, these toxic vapors get released into the environment in that case which will result in a low purge flow code and eventually the purge canister’s demise. And a purge canister’s malfunction may cause permanent damage to your car’s engine.
What is the difference between a purge valve and purge solenoid?
There are no differences between a purge valve and purge solenoid. The canister purge valve of the EVAP system of your vehicle is called purge valve in short and it is also known as purge solenoid. So, a purge valve and purge solenoid are exactly the same, there’s no need to get confused!
Can I drive with a bad purge valve?
You can drive your car with a bad purge valve, but it is highly discouraged. A bad purge valve can lead to numerous problems such as rough idle, lower mileage, ruined gaskets, starting difficulties, emission problems and so on. Persisting with driving with a bad purge valve can lead to complete engine failure, so it is not recommended to drive with it.
How long does a purge valve last?
Usually, a canister purge valve will last for the lifetime of the particular car. However, wear and tear with time and other environmental conditions can often lead to purge valve getting damaged. In that case, you immediately need to replace the bad purge valve.
How much does it cost to fix a purge valve?
The average cost of replacing a damaged purge valve is in the range of $110 to $170. While a purge valve can cost $70 to $110, the average labor fee is around $50. The fixation cost of purge valves depend on the extent of damage, however the labor fees usually remain the same as replacing it.
Can you clean a purge valve?
Yes, you can clean your purge valve. There are two ways to do it. One is by cleaning the valve without opening it and the other is, deep cleaning your valve by opening it with screwdrivers or small knives. However, deep cleaning is discouraged unless you have proper technical knowledge as you can damage the valve permanently.
Can you test a purge valve?
Yes, you can test a purge valve. There are several different ways to test a purge valve.
Conclusion
In summary, purge valves are absolutely essential for your vehicle and even for the environment around you. So, you need to be careful when dealing with it. It should be properly cleaned and regularly tested for any irregularities. Always seek help from your car’s manual or internet, when in confusion. And most importantly, you should always look out for symptoms of a bad purge valve. The moment any symptoms show up, seek professional help immediately.
