Jim Warman - what is a DPFE sensor?

Question

Jim,I had the yellow "Service Engine Soon" warning light come on (2002 EB, 4.0LSOHC) the other day, along with some very minor bucking, only atpart-throttle.  My dealership has drive-up, no appointment service, so,later that day, I drove in.  Last than ten minutes later, it was fixed."2F1Z-9J460-AA SNS ASY EGR PRESS VALVE" was replaced.  The the servicemanager said that the DPFE sensor was not "changing".I like to think I know a good deal about engine controls, but not thisone---it sounds like a pressure-relief valve for the exhaust-gasrecirculation, but I'm only guessing.  I know you're busy, but if you have asecond, could you please tell me what it does?Thanks!

JonnyCabÂ® · Accepted Answer

Make that "Less than".  DUH.I found some stuff on the internet about this.  Does this sensor really failas often as people in some forums seem to say it does?

Jim Warman · Answer

Differential Pressure Feedback Egr sensor..... Looking the the tube that runs from the exhaust manifold, you'll notice the two hoses for the DPFE. Between the two hose nipples is a "waist" or restriction. The DPFE reads the difference in exhaust gas pressure between the two sides of the restriction. The PCM uses this pressure differential to compute how much exhaust is flowing through the EGR valve. The PCM will vary the duty cycle of the EVRV (EGR Vacuum Regulator Valve) to control the opening of the EGR valve to achieve the preprogrammed 'desired flow'.

These sensors live in a very harsh environment and it is not uncommon to see them go south although the sensors on the 4.6, 5.4 and 6.8 don't seem to be quite so troublesome.

HTH.

Jim Warman snipped-for-privacy@telusplanet.net

JonnyCabÂ® · Answer

Jim,Thanks again.  As always, you're the best.

JonnyCabÂ® · Answer

Interesting update---Ford just sent me a letter extending the warranty on this very part (9J460) for an additional 2 years/24,000 miles. It's warranty extension number 02M01.

I got the letter on the same day that I bought a new 2005 Escape Limited.

Jim Warman - what is a DPFE sensor?

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