Anyone else experience repeat DPFE Sensor failure on 97 302's or other years.
I have replace at the following intervals. I will also list vendor the replacement was bought from or brand name.
miles on vehicle miles since replacement
6-24-02 71,980 71,980 original Motorcraft
8-11-04 104,280 32,300 Motorcraft
4-14-07 147,140 42,860 Autozone
11-10-07 157,071 9,981 Autozone
6-20-08 163,695 6,624 O'Reillys
3-05-09 175,721 12,026 O'Reillys
12-15-09 185,366 9,645 out again

Anyone have any ideas as to why there have been so many failures?

 

What exactly is the mode of failure? Melting? KOEO voltage?

 

CEL with P401 and P402 codes. Sometimes one code, sometimes both. Right now it is the P402 code.

 

Ok so it is safe to say the sensor is not the culprit. The codes means EGR flow insufficient. If the sensor gets replaced and the code comes back, then the problem is not the sensor, it means what the code says, that EGR flow is insufficient. Replace the EGR valve and clean the passages.

 

The sensor is the failing part. I have a spare EGR from the past CEL's and when you swap them out [both known good] the CEL comes on almost immediately again. When I replace the DPFE it always fixes the problem for a while then returns. Something is making the DPFE sensors fail, but I don't know what. I always clean or replace the hoses to the EGR when replacing the DPFE.

 

Sounds to me like the sensors are being subjected to some kind of stress they were not designed to handle. Is there excessive shaking or vibration? Are there any heat shields nearby that might be damaged or loose? How are the fuel trims? Have you tested or replaced the EGR solenoid?

 

Engine runs extremely smooth. There are not any heat shields nearby. The manifold that it attaches to gets hot, but the engine is not overheating in any way. The EGR solenoid was replaced but it had no effect of the DPFE. I broke it and replaced it.

I don't know what you mean by the fuel trims.

I have talked to a couple of mechanics and they say it is just the nature of the beast with some of these Ford engines, not all but some. I agree something is causing this but I have no idea what it is.

I plan to switch from Motorcraft 5w20 oil to a 10w30 oil to try and slow the consumption. Maybe this will help.

Still open to ideas.

Thanks for replies.

 

When you replace it again go back with Ford/Motorcraft. Ford has updated this sensor several times since your first replacement purchase. (DPFE15 EGR Pressure Sensor
FEEDBACK - EGR DELTA PRESSURE FEEDBACK (DPFE) SENSOR - F48E-9J460BB, F77E-9J460AB) should be the correct part.

1997 PCED On Board Diagnostics II A SECTION 1A: Description and Operation

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Exhaust Gas Recirculation (EGR) System Monitor—Differential Pressure Feedback EGR
The Differential Pressure Feedback EGR System Monitor is an on-board strategy designed to test the integrity and flow characteristics of the EGR system. The monitor is activated during EGR system operation and after certain base engine conditions are satisfied. Input from the ECT, IAT, TP and CKP sensors is required to activate the EGR System Monitor. Once activated, the EGR System Monitor will perform each of the tests described below during the engine modes and conditions indicated. Some of the EGR System Monitor tests are also performed during on demand self-test.

The Differential Pressure Feedback EGR sensor and circuit are continuously tested for opens and shorts. The monitor looks for the Differential Pressure Feedback EGR circuit voltage to exceed the maximum or minimum allowable limits.

The DTCs associated with this test are DTCs P1400 and P1401.
The EGR Vacuum Regulator solenoid is continuously tested for opens and shorts. The monitor looks for an EGR Vacuum Regulator circuit voltage that is inconsistent with the EGR Vacuum Regulator circuit commanded output state.

The DTC associated with this test is DTC P1409.
The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle.

The DTC associated with this test is DTC P0402.
The Differential Pressure Feedback EGR sensor upstream hose is tested once per drive cycle for disconnect and plugging. The test is performed with EGR valve closed and during a period of acceleration. The PCM will momentarily command the EGR valve closed. The monitor looks for the Differential Pressure Feedback EGR sensor voltage to be inconsistent for a no flow voltage. A voltage increase or decrease during acceleration while the EGR valve is closed may indicate a fault with the signal hose during this test.

The DTC associated with this test is DTC P1405.
The EGR flow rate test is performed during a steady state when engine speed and load are moderate and EGR Vacuum Regulator duty cycle is high. The monitor compares the actual Differential Pressure Feedback EGR circuit voltage to a desired EGR flow voltage for that state to determine if EGR flow rate is acceptable or insufficient. This is a system type test and may trigger a DTC for any fault causing the EGR system to fail.

The DTC associated with this test is DTC P0401.
DTC P1408 is similar to P0401 but performed during KOER Self-Test conditions.
The MIL is activated after one of the above tests fail on two consecutive drive cycles.





Figure 15: EGR System Monitor - Differential Pressure Feedback EGR



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I replaced the DPFE sensor with a new one from O'Reillys that was replaced under the lifetime warranty. The Mountaineer now has 189,300 mile so I have driven around 4000 miles without another failure at this time.