B2500 dpfe sensor

[brianb]

So, check engine light, code ran for a new DPFE sensor, replaced with aftermarket and got code again....I have read some people have had voltage issues, some had better luck finding old motorcraft sensors....anyone have luck with aftermarket sensor and is there something else I can check besides trying a new sensor?

 

[RonD]

Never seen a "bad DPFE sensor" code, what was the code number?

There are a few codes that mention DPFE sensor but they don't mean sensor is bad.
P1401 on Fords does "usually" mean sensor is bad, but not always.

The DPFE sensor hoses are connected to the exhaust system, which means they will get moisture inside.
Gasoline(H) burned with oxygen(O) has a byproduct of H2O(water), which is why exhaust systems rust from the inside out and why tail pipes often drip water.

The moisture in the hoses can kill the DPFE sensor, so check the hoses, blow them out.

The 2 hoses are connected to different places on the exhaust, one closer to EGR valve one farther away.
The DPFE(differential/delta pressure feedback) sensor measure the pressure difference between these 2 hoses.
When EGR valve opens the pressure on the closer hose is less, how much less is how the computer knows how far open the EGR valve is.

The DPFE system works better than the older system because the computer can compensate for the EGR valve and tube getting a build up of carbon which restricts the flow of exhaust gasses into the intake.

You can test voltages on 2 of the 3 wires.
Computer sends DPFE 5volts on 1 wire
DPFE sends back .5v to 1volt on another wire, depending on DPFE sensor model, when engine is off, key is on
3rd wire is a ground

The 1volt wire is often much higher, above 2volts, when DPFE sensor fails, that's the P1401 "Diff Pressure Feedback EGR Circuit High", so replacing the DPFE is often a good gamble, but it is still a gamble, could be 5v wire and 1volt wire are shorting, rubbing.

If you apply a vacuum to one hose(just suck on the hose) the voltage will increase on the 1v wire up to 4.5v max., but the fact it increases at all means it is most likely working, so you don't need to suck to hard, lol.

I find a sewing needle works well to pierce a wire so I can test voltage on that wire while it is still connected.

Found this: http://www.tomco-inc.com/Tech_Tips/ttt36.pdf