EGR and dpfe issue

DuKeNoMaD

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So had the EGR low flow code forever, changed the dpfe sensor...now no low flow code but dpfe high voltage code ..wtf...should I blame the sensor being faulty?
 

AmsterDutch

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So had the EGR low flow code forever, changed the dpfe sensor...now no low flow code but dpfe high voltage code ..wtf...should I blame the sensor being faulty?
Check the wirings... Use a multimeter and measure the signal, ground, and voltage. Make sure you have 5 volts on the voltage wire and proper ground. If the signal/voltage is not in the range of 0.2 to 4.8 voltage, the P1400 or P1401 will set.
 

AmsterDutch

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FWIW...you could always take off the egr and clean it with carb cleaner ...maybe the valve is stuck...I'd suggest replacing it back on with a new gasket
 

capt fast

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So had the EGR low flow code forever, changed the dpfe sensor...now no low flow code but dpfe high voltage code ..wtf...should I blame the sensor being faulty?
what are the odds, new part bad. use oem sensors to avoid the issue.
Usually, I kinda trust sensors and instruments, just my training. a low egr flow code to me won't mean the sensor is bad right off. I would have to prove the sensor is bad. I would first have suspected the flow was low and started from there.
the pipe from the exhaust manifold to the egr valve has a quite small orifice in the tube between the ports on the pipe that the egr/dpfe picks off the differential pressure signals from.it looks like a washer stuck in the tube. when the egr opens, the dpfe is looking for a change in pressure on each side of that orifice. that could be plugged or at least partially blocked, a hose leaking, a bad sensor or barring any of that; God is angry with you for some past life's activities. low flow means the pressure on each side of the orifice is almost equal,a blocked orifice would cause a high flow indication as pressure difference across the orifice would be great. so.
the egr valve could be plugged. the egr has usually a position sensor on the valve but there could be an internal failure of the valve and the position sensor won't see that as it is looking at the vacuum valve pintle position and not the actual valve pintle position. if it is working ok and not blocked you'll be looking downstream from the egr valve. the egr gasses distribution lines and ports may be plugged. some models only port gasses just after the throttle body and some run a port down to intake port at the cylinder head to the individual cylinder intake ports. exhaust gasses are dirty and vaporous looking for someplace to condense. finding this kind of problem may involve pulling the intake manifolds.
crap in the ports anywhere in the system would cause a low flow condition. dpfe systems are very sensitive to this.
for what it's worth, that is the extent of the problems I have run into.
 

DuKeNoMaD

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Oh I understand how the system works, just was more annoyed than anything. I took my multimeter and checked resistance between the factory motocraft piece, and then on the replacement....vastly different. I cleaned up the old one and high voltage code went away. And yes I suspected the EGR from the beginning but they are a few weeks away to order( for a decent $) and this was a quick test. Just wanted to clear all the codes before it went to inspection today. Thanks for your input.
 

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