A dpfe sensor is an engine component that monitors the amount of emissions that are sent back in the combustion system then communicates with the powertrain control module. The DPFE sensor (Delta pressure feedback of EGR) is used to inspect the exhaust pressure changes above and below a metered orifice.
The DPFE sensor converts the output pressure into an analog signal and sends it to the computer system to calculate optimum EGR flow. Dpfe sensor monitors the pressure changes of the Exhaust Gas Regulation (EGR) system. It reduces the quantity of nitrogen oxide being emitted through the exhaust.
ERG is the process of sucking gases that are exhausted by the combustion system back to the engine to re-burn them. Also, it is a requirement by law in many countries to add an exhaust Gas Regulation system to motor vehicles.
EGR System Basics
High temperatures and pressure are the basic requirements for production of Nitrogen Oxide. When these two requirements are regulated, the amount of Nitrogen Oxide emitted can also be controlled.
This is achieved by sending the emissions back to the combustion system, reducing the ignition temperature and lowering the pressure to produce less nitrogen oxide. The EGR system is believed to reduce this gas emission by 60%. Dpfe sensor, therefore, monitors the efficiency of the EGR.
If an increase in the flow of EGR is required, the powertrain control module (PCM) valve rises the duty cycle into the Electronic vacuum regulator. The increase in duty cycle permits more vacuum to get in EGR valve thus opening the pintle wider consequently increasing EGR valve flow.
If low amounts of EGR valve flow are required, PCM reduces the duty cycle to the Electronic Vacuum Regulator (EVR). If the desired flow is achieved, the PCM regulates the duty cycle to EVR at a constant rate.
The PCM is also used to monitor the Manifold Absolute Pressure sensor, Engine Coolant Temperature, Throttle Position Sensor, Mass Air Flow and the DPFE sensor to establish the right quantity of EGR flow that is required.
When the right amount is determined, the PCM sends the suitable signals to the Electronic Vacuum Regulator solenoid to precisely control the EGR flow.
Symptoms of a Bad DPFE sensor
There are only a few to look for when it comes to knowing the different symptoms of a bad DPFE sensor. Here are the top signs that your vehicle may show:
Check engine light warnings
If you notice that the check engine light comes on when you have rough idling problems, you will most likely probably have a problem with your EGR system. It is not guaranteed that you have a problem with the DPFE sensor, but it’s most likely a problem with your engine.
Poor engine performance
Once you start noticing that your vehicle has lost power when accelerating, this is a significant indicator that it could be a problem that is related to the DPFE sensor. This will also decrease the fuel economy performance, and your vehicle will start to consume more fuel than usual.
Failing an emission test
An emission test would be something that a professional mechanic will run to confirm if there is a problem related to any vehicle ERG systems. A failing exhaust gas recirculation test could potentially lead to a DPFE sensor replacement.
What happens when the DPFE sensor fails?
It is not a guarantee that dpfe sensors that come pre-installed in vehicles will always function as expected. The DPFE sensor will sometime in its life time fail and start sending the wrong information to the powertrain control module. The PCM valve controls the amount of exhausted air that is mixed with gasoline before it is sent to the engine.
When the EGR system fails, the PCM valve starts generating a slender mixture. This slender mixture causes a vehicle to do unfamiliar things like staggering, lurching or jumping. It is, therefore, important to maintain this sensor in good condition to optimize the EGR functioning.
When the dpfe sensor fails, it becomes less sensitive and the PCM reacts like there is a reduction in the recirculated nitrogen oxide gas than it should be. To burn more gas, the PCM valve opens the actuator than the required limit. Eventually this leads to the production of the lean mixture.
The DPFE sensor should, therefore, be replaced every 30k miles travel distance. DPFE sensor failure process is slow and sometimes it is realized after it is destroyed. Regular checks should therefore be conducted to establish the efficiency of this small device.
How To Fix The DPFE Sensor
If you experience some stumble or hesitation while traveling, this might be the high time to change the dpfe sensor. However, it is advisable to seek other reasons that might cause the same effects.
In many engines, the DPFE Sensor is a zipped Black box pinned to the firewall with a bolt mostly at the top middle. There are two rubber hoses that drop from the black box and a three wire plug perpendicularly going to the firewall.
The two rubber hoses drop to the EGR pipe of 0.5″ in diameter. This is the pipe that comes off at the driver’s side of the exhaust. It then goes around the side of the driver of the engine under the coil pack.
The DPFE sensor in some engines is a square black box that has a 3-wire plug at the top with two hoses that come from the bottom side. This box sits at the top of the EGR pipe and is located slightly under air consumption tube.
Additionally, the box connects to the EGR pipe through the rubber hoses. However, the hoses are short and upright. There are two different dpfe sensors at this point but are situated in a similar place and look alike.
Fixing the dpfe sensor most times involves replacing the old one. It is advisable to follow the right procedure to successfully replace this device. The initial thing to do is to release the battery clips to ensure there is no current flow.
You then proceed to unplug the electrical connector located at the front of the connector then remove it from the two black hoses. At this point, you need the right bolt removers to loosen the bolts. With ease, move the sensor sideways if it is tight to avoid breaking the inlet fittings from the sensor bottom.
After the sensor is removed, the new device should be installed in reverse order while making sure that the two black hoses are properly fixed at the right positions. For more secure installations, it is advisable to tighten the sensor with zipping ties.
The electrical connector should be put back into its original position then place the battery clips into their appropriate terminals. To ascertain that the dpfe sensor is working as require start the vehicle and observe its operation.
Delta Pressure Feedback Sensor Replacement Cost
Most regular car owners would not even know that the DPFE sensor exists until they start having engine problems. Some of the issues related to the EGR valve include rough idling, lousy engine performance, or even low power consumption.
Even if your car starts to show some of these symptoms, you will not notice that the EGR system fails until your vehicle light up the check engine light, or it has a failed emissions test. So, what is the cost of replacing a bad differential pressure feedback of EGR system?
The price of replacing a bad DPFE sensor and EGR valve would vary depending on the type of vehicle that you own. Typically, the replacement cost would be around the range of $125 and $600 of the total price, including labor. Remember that these prices can vary depending on where you live and if you are willing to do it yourself.
DPFE Sensor Troubleshooting Tips
- By using a multimeter you can actually check the wire harness, and verify if there is an open circuit .
- Go on your owner’s manual to see where the vacuum hose is located and verify that it does not have any cracks.
- If you have a OBD2 diagnostic tool on hand check if you get trouble code P0131 with regards to bad oxygen sensors.
- Check the vacuum line that connects the intake manifold to the EGR actuator.
DPFE sensor Summary
It is important to keep a vehicle in its optimal operation capability. The automotive dpfe sensor is one of the devices that ensures your vehicle operation is monitored. If the right procedure is followed in replacing this device, minimal or no release of nitrogen oxide are witnessed.
This has a ripple effect conservation of environmental air since there is complete combustion of exhaust gases released through the exhaust pipe. All vehicle owners should, therefore, keep track of their engines and test the dpfe sensor. Scan tools like the OBD2 diagnostic tool could identify if there is a problem with the EGR system.