How to Test a Fuel Pressure Sensor with a Multimeter

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You will find thousands of parts that have worked together to make your vehicle function correctly. Did you know that the average driver understands the basic components, things like coolant reservoir, brake lines, transmission, and so on? Still, even most of these components are made up of many smaller components. 

Bear in mind that your fuel system that many people are aware of has a lot of tinier parts, including a fuel pump, filter, and of course, your fuel tank pressure sensor. 

A fuel pressure sensor is a part of the fuel pump assembly. It belongs to the evaporative emission system that’s often shortened to EVAP. That sensor is essential for the overall functioning of your car. When something goes wrong with it, that could cause serious concerns. 

What is a fuel tank pressure sensor? 

As you can guess, a fuel pressure sensor is a sensor reading pressure in the fuel system. It helps you determine if you have any leaks, particularly ones caused by evaporation. That’s the reason it’s part of the EVAP. 

It also means if you have a bad gas cap, it will tell you that you have some fuel leaking out there or if there are vapors leaking anywhere else where they should not be. 

The information gathered by the fuel pressure sensor is then delivered to your engine computer. The check engine light will show up on your dashboard when it detects an issue with the pressure. It will let you know you have an issue that should be dealt with immediately. Apparently, a check engine light by itself does not suggest that you have an issue with that specific sensor. 

What happens if your fuel pressure sensor starts malfunctioning?

 You will find both good news and bad news when it comes to learning what happens if your fuel pressure sensor goes bad. The good news is that it is possible that your vehicle will still function fine. It may not change the way your car performs at all.

Nonetheless, the issue is that you are not going to pass emissions testing when the sensor is not working the way it is supposed to. Certainly, you need to check the engine light which could be a nuisance. Ignoring it because you believe it is only the fuel pressure sensor that set it off, and something else happens will lead you to not know that you have another problem to check. 

You will find a few symptoms and signs you need to pay attention to with your fuel pressure sensor. Here are some of the things you need to consider:

  • Bad fuel efficiency

Does your computer not have the correct information concerning how much fuel you are using or how much fuel you need to burn to sustain speed? Then you could end up burning too much fuel and getting bad performance too. You will also receive lower miles per gallon and might have problems with the acceleration. 

  • Difficult starts

You may find it challenging to get your car started if you have a bad fuel pressure sensor. You may not be having the correct amount of fuel delivered to your engine to burn if it is sending the incorrect information to your engine’s computer.

You may have difficulty starting your car as a result of having a lean fuel mixture. 

  • Stalling

Do you often find your vehicle stalling? That could be a sign of a bad fuel pressure sensor. The data from the tank pressure sensor helps control the fuel to air ratio required for the combustion reaction in your engine. Hence, it could begin sending wrong signals that lead to your engine not burning fuel properly. 

  • Check engine light

A check engine light will come on the instant you have a problem with a malfunctioning fuel pressure sensor. If you have an OBD2 scanner, a code P0452 will appear. That’s something you like to get checked right away as it could indicate you have a leak in the fuel system too. 

How Do You Test a Fuel Pressure Sensor? 

 A fuel pressure sensor is not a very complicated technology. It runs on a three-wire circuit that is simple to learn. The sensor boasts a reference voltage wire coming from the computer of your car, a ground wire, and one that reverts voltage to the powertrain control module. Hence, if there’s an issue with your pressure sensor, you just need to check the three wires. 

One device that can help you with testing is a digital multimeter.

  1. Remove the sensor from your vehicle. You can always refer to your car’s manual if you have little understanding of the sensor’s location. 
  1. Start your vehicle and grab your multimeter. Connect the probes of the meter to the wires. Connect the red probes to the positive wire and the black probe to the negative wire. 
  1. Check the readings of the meter. Refer back to the manual to determine if the test results are good or bad. That will offer you an idea of the best voltage specifications. 
  1. Now, are the values different or within the range? Wrong values would indicate there’s something that’s stopping the sensor from detecting the correct pressure or your entire system is malfunctioning and need immediate replacement

As you can tell, the fuel pressure sensor is an integral part that many drivers are not even familiar with. The sensor data is very important for ensuring your vehicle is functioning at maximum efficiency in a way that will save you money, enhance your gas mileage, and keep your car working. 

Final Thoughts

There you have it! We hope this post has clearly explained to you what a fuel pressure sensor is and how you can check it with a multimeter. After you become knowledgeable about the components and operation of the meter, the whole process becomes relatively simple.

The next time you believe you are losing out on horsepower or encountering backfiring, we can expect you to bring out your digital multimeter and get to the root of the issue.

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