With advances in technology and especially in automotive engineering, cars have experienced some significant improvements over the years.
A modern car today has so many parts and electronic sensors that take over much of the driving and fuel combustion of your car. Of all these sensors, one is the DPFE sensor. DPFE is short for Delta Pressure Feedback of EGR, the purpose of which is to monitor the pressure changes of the EGR.
All this may sound very confusing, as even many car fanatics don’t normally hear the name DPFE or EGR, but don’t worry because after reading this you will get a firm idea of this sensor and its function.
In this article, we will discuss the function, symptoms, troubleshooting and replacement costs of the DPFE sensor.
What is a DPFE sensor?
As we just mentioned above, the DPFE sensor is the Delta Pressure Feedback of the EGR. We will talk about EGR later. The DPFE sensor is one of the components of your engine that is used to monitor all the air coming back into the air intake from the exhaust. Yeah, you heard it right. To improve efficiency, cars use the air that comes out of the exhaust, also called exhaust air, and reuse it for combustion. The way it works can be associated with a turbo system. The turbo system contains a turbine inside, which is driven by the exhaust gases that your car releases. This exhausted air drives the turbine, which in turn draws in the fresh, cooler air in the intake much faster and with a lot of power, giving your engine a real boost.
While the DPFE sensor is in direct contact with the exhaust gas, it does not take over the supply of exhaust air. This part is controlled by the EGR system, which we will talk about later in this article. However, the DPFE sensor monitors the pressure difference in the air and the amount of air entering the engine and gives feedback to the EGR system according to the readings, hence the name “Delta Pressure Feedback of EGR”.
In a sense, the DPFE sensor informs the EGR system how much air to let in, taking into account the situation.
Ford DPFE sensor Function
The DPFE sensor checks the pressure of the extracted air and the pressure changes by means of an orifice. The output that the sensor receives is then converted into an analog signal. This signal is then sent to the vehicle’s computer system to be compared with previous readings and used to control the EGR for optimum airflow. From there the computer sends a signal to the EGR system to control the exhaust air. The main purpose of the EGR system is to reduce the amount of nitrogen oxide that the engine releases during combustion.
Ford often uses the DPFE sensor for its various vehicle models. The most common car model is probably the F-150.
EGR, which stands for “Exhaust gas recirculation“, is a mechanism that controls exactly what the name suggests. The EGR system consists of a valve that controls the exhaust air returning to the engine. The exhaust gas is reused depending on the combustion factors of the fuel.
The fact is that the mixture of fuel and air produced by the carburetors or the throttle valve is not completely burnt and each time a part of it is burnt and a part of it leaves the exhaust in the form of gas that is not 100% burnt.
The recirculation of this unburnt gas ensures that it is re-combusted completely the second time, thereby improving fuel efficiency and, above all, controlling car emissions.
An unburned mixture leads to the production of various harmful gases, one of which is nitrogen oxide, which is released into the atmosphere. As many states have now passed legislation and set the permitted emissions, the proper functioning of the EGR system has now become compulsory.
The EGR system is quite simple and consists of a single valve that opens and closes to the amount specified by the car’s computer. Older cars have mechanical EGR valves, also called pneumatic valves, while modern cars have electronic EGR systems that are precisely controlled by the car’s computer.
Main functions of an EGR valve
- To reduce the throttle loss on gasoline engines.
- To increase engine life by preventing extreme engine temperatures due to the accurate burning of fuel.
- To reduce emissions.
What happens if the DPFE sensor fails?
Like other parts, sensors tend to fail eventually. Although it is unusual for such sensors to fail, a number of factors can cause premature failure. Because the DPFE sensor’s job is to provide accurate readings to the EGR, the sensor will give incorrect readings if it fails. If the DPFE outputs the wrong signals, this will cause the EGR system to operate inaccurately. If the EGR system is not working properly, the PCM valve, which controls how much air is added to the fuel, starts to produce a lean mixture of air and fuel.
The failure of the DPFE sensor will eventually cause the PCM to produce a lean mixture, as it thinks that the circulation of exhaust air has decreased.
Bad DPFE Sensor Symptoms
There are many different signs to look for when you are confronted with a bad DPFE sensor. Here are some of the most common symptoms.
1. Reduced engine performance
If you notice that your car starts to run rough and wobbly when idling, this may mean that the DPFE sensor is not working as it should. In such cases, the engine also hesitates when you push the accelerator pedal, and you may feel a loss of engine power.
2. Check engine light comes on
If you are experiencing the above problems and your check engine light comes on at the same time, it could mean that your engine control unit has detected a problem with the DPFE sensor. If the engine check light is on, it does not necessarily mean that there is a problem with the DPFE sensor, but it could be.
3. Your car may fail the emission test
This is probably the easiest symptom to look for. If your vehicle fails the emission test, you may have a problem with either the DPFE or EGR system.
DPFE Sensor Troubleshooting & Testing
If you have some knowledge about cars and troubleshooting, you can test the DPFE sensor and the wiring for it at home. Here are some simple things you can check for yourself with the help of a multimeter and basic knowledge about its use.
Check the vacuum hoses: Check for cracks or broken hoses between the EGR and the DPFE sensor.
Check the wiring: Use a multimeter and measure the signal, ground, and voltage. Make sure that there are 5 volts on the power cable and that it is properly grounded. If the signal/voltage is not within the range of 0.2 to 4.8 volts, the P1400 or P1401 error codes will occur.
Measure for an open circuit or short in the DPFE Sensor: Use a Multimeter
Check the EGR valve: Check for blocked hoses or jammed EGR valve
DPFE Sensor Replacement Cost
It’s best to replace the DPFE sensor if you’re having problems such as rough idling and low power consumption because if you set the sensor to trick the system into thinking that everything is working fine, your car will not pass the emissions test. This can lead to legal problems and also shorten the life of your engine.
Depending on your particular car, replacing the DPFE sensor along with the EGR valve should cost between $150 and $500 including labor, which also depends subjectively on where you live.