How to check the purge valve with a multimeter
Content
The purge valve is part of the vehicle's Evaporative Emissions Control (EVAP) system. The mechanism helps prevent fuel vapors generated by the engine from escaping into the environment or back into the vehicle. He temporarily stores them in a charcoal canister. The valve also helps control the amount of fuel vapor that is eventually blown out of the charcoal canister.
In modern vehicles, the system is an electronically controlled solenoid connected to engine power. The purge valve gradually turns on as soon as the ignition is turned on, but the EVAP system also does not work when the engine is off.
There are times when the system fails, which harms the health of your car! This is handy when you know how to test the purge valve with a multimeter. Apart from this, we will also discuss the following points:
- Consequences of failure of the adsorber purge valve
- Should the purge valve click?
- Can a bad purge valve cause a misfire
Ways to test the purge valve with a multimeter
The aptly named multimeter is a handy device that can measure voltage, resistance, and electric current.
To test the purge valve, check the resistance between the terminals.
The procedure may differ depending on the vehicle model, but the basic steps remain the same.
Listed below are the general steps that can be used to test a purge valve that is part of an EVAP system:
- PositioningThe first thing to do is turn off the engine for at least 15-30 minutes. After that, try to find the car's purge valves. Ideally, it can be found behind the muffler or muffler and positioned on top. This is an EVAP carbon filter with a purge valve inside. For more information on the location of the system, try searching the vehicle's owner's manual or looking for a model online with an engine picture.
- Cable adjustmentOnce you find the purge valve, you will see that a 2-pin harness is connected to the device. The next step is to disconnect and reconnect them using the multimeter adapter cables that are usually included in the test kit. They can also be purchased separately. The purge valve terminals must be connected to the multimeter cables.
- The test is The last step is to measure the resistance. Ideal levels should be between 22.0 ohms and 30.0 ohms; anything higher or lower will mean the valve needs to be replaced. This can be done on site if you have a spare; otherwise, if you want to take it to the store, be sure to reconnect the wiring harnesses as before.
How do I know if my purge valve is faulty?
There are many symptoms of a malfunctioning EVAP system. Pay attention to:
Engine light The engine controls the purge solenoid and if something goes wrong, the engine light will come on. If a higher or lower level of purge vapor is detected, error codes are displayed, including P0446 or P0441. We recommend taking the car to a repair shop if you notice the above signs.
Engine problems If the purge valve is not closed, the air-fuel ratio may be adversely affected by escaping vapors to the environment. The engine will respond to the change, resulting in difficult starting or rough idling.
Less gasoline consumption When the EVAP system is not working efficiently, it inevitably reduces gas mileage. Instead of accumulating in the purge valve, fuel vapor will begin to seep into the environment, causing increased combustion of the fuel.
Poor performance in the outlier test The EVAP canister is responsible for redirecting fuel vapors back to the engine. This helps prevent the release of toxic fumes into the environment. In the event of a faulty solenoid, it will not be able to control smoke and fail the emissions test.
Destroyed pads Since the vapors will not be able to pass if the valve fails, the pressure will begin to build up. Over time, it will become so intense that it can blow out rubber seals and gaskets. The consequence will be oil leakage, which can enter the main engine from the exhaust system, causing serious damage. The most common reason for a blowdown valve to work perfectly is that pieces of carbon or foreign material are stuck, leaving the mechanism partially closed or open. Needs replacement or cleaning.
Should the purge valve click?
The short answer to the question is yes! The purge valve usually makes a clicking or ticking sound. However, in a car with closed windows, it should not be noticeable. If it gets too loud and can be heard inside the car, it can be a cause for concern. The solenoid needs to be checked.
One possibility is that the purge valve began to let vapor into the engine when refueling. This will lead to rough startup and issues as mentioned above.
Can a bad purge valve cause misfiring?
A faulty purge valve can lead to a misfire if the situation is left unattended for a while. As fumes begin to build up excessively in the EVAP system or in the charcoal filter, the valve will not be able to open in time.
If the process continues over time, fumes will seep into the engine cylinders, resulting in the combustion of abnormal amounts of fuel and fumes. This combination will cause the engine to stall and then misfire. (1)
The final verdict
The solenoid valve is an important vehicle component. If you notice any of the problems listed above, the car should be repaired immediately. If you want to test the canister yourself, you can follow the steps with a multimeter and the device will tell you if you have a bad valve! (2)
Since we have presented you how to check the purge valve with a multimeter, you can also check. You might want to check out the best multimeter selection guide and decide which one suits your testing needs.
We hope this tutorial article will help you. Good luck!
Recommendations
(1) EVAP system - https://www.youtube.com/watch?v=g4lHxSAyf7M (2) solenoid valve - https://www.sciencedirect.com/topics/earth-and-planetary-sciences/solenoid-valve
