Your car’s fuel delivery system is made of several components that work collaboratively to supply the engine with enough gasoline upon demand. One of these parts is the fuel rail pressure sensor, which assists the powertrain control module (PCM) in managing the fuel delivered to the engine.
But what happens when the fuel rail pressure sensor fails? How do you know when it’s time to replace your failed or broken part? Is it okay to drive your car with a broken sensor, even if it’s just to your garage or the auto shop?
What is a Fuel Rail Pressure Sensor and How It Functions?
A fuel rail pressure sensor is an electronic instrument that records the amount of pressure in the fuel rail, the metal tube that sends fuel from the fuel delivery system to the engine. Sometimes this part is called a fuel pressure sensor or high-pressure sensor.
A fuel rail pressure sensor uses a semiconductor and an electrical device to measure the force exerted by the fuel moving through it. The fuel pressure changes the resistance in the semiconductor. The electronic circuit converts these changes into a digital signal that is received by the PCM.
Where is the Fuel Pressure Sensor Usually Located?
The fuel pressure sensor is usually mounted somewhere on the fuel rail on the engine, which distributes fuel to the fuel injectors. In this case, it would likely be mounted on the outside of the engine. It can be pushed to the side somewhere, or it could be located directly on top.
The fuel pressure sensor monitors the fuel pressure in the fuel rail and sends that information to the powertrain control module (PCM).
Many engines have two fuel pressure sensors. In the case of a 2013 Chevrolet Equinox, there is one fuel pressure sensor on the fuel rail, and it is located right behind the intake manifold, and there is also one located underneath the engine near the driver’s side wheel.
Gasoline direct injection (GDI) vehicles, like the previously described Equinox, may have two fuel pressure sensors, one on the high-pressure fuel rail and the other on the fuel supply pipe on the low side.
Some GDI vehicles do not have low-side fuel pressure sensors. However, GDI vehicles will always have a fuel rail pressure sensor located on the high-pressure fuel rail.
Signs of a Bad Fuel Rail Pressure Sensor
Most fuel rail sensors will last for at least as long as the vehicle lasts. However, even a fuel pressure sensor can fail early. A failed sensor will usually show at least one sign that it is not working correctly, at a minimum.
Signs and symptoms of a failed fuel rail pressure sensor include:
#1. Check Engine Light.
A faulty fuel rail pressure sensor can cause the “Check Engine” warning light on your dashboard to turn on. This light will turn on when the engine control unit detects a problem inside the vehicle impacting the engine in some way.
That doesn’t always mean that the engine itself is bad, as it can sometimes mean that something else in the vehicle is stopping it from doing its job to the best of its ability.
You probably won’t immediately know it is the fuel rail pressure sensor, but a diagnostic scan tool can usually pinpoint the issue.
DTC codes P0190, P0191, P0192, P0193, and P0194 are the most common DTC codes for fuel rail sensor issues.
#2. Difficulty Starting Engine.
When you have a bad fuel rail pressure sensor, the ECU won’t send the correct amount of fuel to the engine, making it difficult to start your vehicle.
When the first issues begin, you will likely need to crank the engine a couple of times before it starts, though as the problem worsens, you will need even more cranks to start. Sometimes it will start and then immediately shut off. Eventually, you may be at a point where it doesn’t start at all.
#3. Weak Acceleration.
If you push down the gas pedal and the vehicle does not accelerate, you could have a bad fuel pressure sensor.
The engine control unit is not able to send the signal to the fuel system properly, as it is receiving inadequate information from the sensor. Therefore, the ECU will not know how to accommodate the fuel demands on the engine.
#4. Stalling.
Stalling while the fuel rail pressure sensor goes from bad to worse may occur when driving or when idling. You will be driving, and then all of a sudden, your engine will stall.
This will cause driving badly, and even if it is not dangerous for you, it should motivate you to do something about it. If it turns out to be the fuel pressure sensor, then take your vehicle to the nearest auto shop and get it replaced.
#5. Bad Fuel Mileage.
With a non-functioning fuel pressure sensor, such as when it is bad, you will see a significant lack of fuel economy and mileage.
Either the ECU will be sending too much fuel or not enough fuel through the fuel rail and into the combustion chamber. You will be making more trips to the gas station and causing your pocketbook to quickly become lighter.
Most with larger vehicles will usually notice a greater reduction in fuel economy. For example, the fuel economy of a Duramax engine will be affected more than something like a Honda Civic.
Fuel Sensor Replacement Cost
The cost to replace the fuel rail pressure sensor will vary quite a bit depending on the make and model of your vehicle. On average, the total cost will be between $200 and $340 to replace the fuel rail pressure sensor.
The parts will be between $60 and $100, and the labor cost to replace the sensor will cost you between $140 and $240.
Of course, you will generally pay much more at the dealership to have the work completed than an independent mechanic. Unless you have a lot of auto repair experience, you should not normally consider doing the replacement yourself.
What Causes the Sensor to Fail?
Here are two of the leading causes of known fuel rail pressure sensor failures.
Pollutants
Exposure to pollutants and impurities in the fuel is the leading cause of clogging and damage to a vehicle’s fuel pressure sensor, which eventually leads to failure. These impurities will build up in the sensor over time and cause it to malfunction.
This is a great reason to avoid using cheap gas at gas stations you have never heard of, to not only keep your engine running smoothly, but also prolong the life of your fuel pressure sensor, as well as any sensors.
Wear and Tear
Like anything else in your vehicle, fuel pressure sensors eventually wear out and fail. Because it is part of the pressurized fuel system, as the fuel pressure sensor wears out, it resembles not being able to adjust the fuel pressure as intended, which results in engine performance issues, and failure of the sensor eventually.
Is It Safe to Drive with a Bad Fuel Rail Pressure Sensor?
Yes, you can drive with a bad fuel rail pressure sensor, but is it a good idea to? The answer is no. In most cases, you will start to notice other symptoms, such as poor performance, difficulty starting, or stalling.
Not only will these symptoms likely annoy you, but they also can create huge safety risks when you are out on the roadway. Seriously consider what would happen if you were to stall out at a busy intersection or lose power while towing your trailer up a steep hill.
So, our advice is to not cut corners, and get it looked at and have the sensor replaced before it creates an even bigger headache for you at the worst possible time.