DPFE Sensor Symptoms, Functions and Fixes

What is a DPFE Sensor? Symptoms, Functions & Fixes

A DPFE sensor is an engine part that monitors the number of emissions that are sent back in the combustion system then communicates with the power-train control module. This sensor is used to examine the exhaust pressure changes above and below a metered orifice. The detector converts the output pressure into an analog signal and transmits it to the computer system to determine optimum EGR flow.

What does DPFE, ERG and PCM stand for?

ERG is the process of absorbing gases that are exhausted by the combustion system back to the engine to re-burn them. The DPFE sensor monitors the pressure fluctuations of the Exhaust Gas Regulation (EGR) system. To decrease the level of nitrogen oxide through the exhaust, it is a requirement by law in many countries to add an Exhaust Gas Regulation system.

High temperatures and pressure are the basic requirements for the production of Nitrogen Oxide. When these two requirements are regulated, the amount of Nitrogen Oxide emitted can also be controlled. That is achievable 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, therefore, monitors the efficiency of the EGR.

If an increase in the flow of EGR is required, the power-train 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 flow. If low amounts of EGR flow are required, PCM reduces the duty cycle to the Electronic Vacuum Regulator (EVR).

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 correct amount is determined, the PCM sends the suitable signals to the Electronic Vacuum Regulator solenoid to precisely control the EGR flow.

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 sensor will sometime in its lifetime fail and start sending the wrong information to the power-train control module. The PCM valve controls the amount of air that combines with gasoline before sending it to the engine. When the EGR system fails, the PCM valve starts generating a slender mixture. This slight mixture causes a vehicle to do strange things like staggering, lurching, or jumping. It is, therefore, essential 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. 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 sensor problems

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. Two rubber hoses drop from the black box, and a three wire plug is perpendicularly going to the firewall. The two rubber hoses fall to the EGR pipe of 0.5″ in diameter. That`s the pipe that comes off at the driver’s side of the exhaust. It then goes around the bottom 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. The table also 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 return this device successfully. The first 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 fixed adequately 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 sensor is working as required to start the vehicle and observe its operation.

Safety Precautions when changing a DPFE sensor

DPFE Sensor Safety Precautions Infographic

Conclusion

It is vital to keep a vehicle in its optimal operation capability. The 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. That has a ripple effect conservation of environmental air since there is complete combustion of gases released through the exhaust pipe. All vehicle owners should, therefore, keep track of their engines and take actions when they suspect any malfunction.

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