How do test the DPFE?

[simmons1]

My CEL keeps coming on with code 401. I know that it is insufficient EGR flow. I am fairly sure that my EGR is ok, because the valve moves easily. So now I think that the code is caused by the DPFE. I have seen references of a "DPFE test" in search engine, but no one describes the test. Does anyone know how to perform this test? Thanks!

 

[chadb]

EGR

It it really hard to check an DPFE. It senses differential presure. You might check the EVR Solonoid(not sure how) I think it's called that controls the EGR also unless your model has it built into the EGR. I recently replaced my DPFE after getting EGR error codes. Inspecting it showed a lot of corrosion on the entry points into it. Probably corroded the sensor. Replacing it fixed my problems.

 

[simmons1]

I noticed that when I took off the DPFE that there was some corrosion inside the tubes. That just makes me think even more that this is my problem. I just want to make sure. I can afford to play cat and mouse with this.

 

[Glacier991]

Clean out the tubes, and if you want try blowing some brake cleaner thru the DPFE. It's calibrated so don't go poking wires in it or anything. I doubt this willl fix the problem, but you can try it. If not replace it, and make sure the hoses are clean. 99% of the time your problem will go away with DPFE replacement on a code 401. If you want you can test the output voltage, but candidly, replacement is usually the correct course on this one.

Happy exploring

Chris

 

[simmons1]

Thanks Chris. I tried the brake cleaner route, but sure enough after a 50 mile drive the CEL came back on. Do you know the correct output voltage? If would like to test it before buying a new one?

 

[Glacier991]

My books say that for code 401, voltage is outside limits... eg. greater than 4.96 or less than .195 volts. or that the EVR solenoid driver indicates a short. HTH

Chris

 

[dogfriend]

I have a scan of the test from my EEC book. Sorry about the poor quality. They have a chart with voltage vs. applied vacuum. If you have a voltmeter and a hand operated vacuum pump, you can test the DPFE using these values

If you can't read the values, email me and I can email back a PDF copy which is easier to read.

 

[simmons1]

Thanks guys this is great!