I still have the same problem. The manifold and EGR valve are clean, so its not a blockage issue. I have battery voltage at the EGR control solenoid. I can disconnect the vacuum line going to EGR valve and suck on it and here that the valve is operating smoothly. When I start the truck and leave it in park, the EGR pipe stays cool. Then when I put it in gear, the pipe gets hot like everything is working normal. All the vacuum lines appear to be in good condition also.
Still getting the PO401 code.
I dont have my own scan tool, i've been going to the local auto parts store to have them check the code. I did take some voltage readings with a meter and this is what i got at the DPFE connector.
disconnected and engine not running: 5v at brown/white to gray/red.
5v at brown/green to gray/red.
And with plug hooked up and engine running and warmed up:
1v at brown/green to gray/red
4v at brown/white to brown/green
5v at brown/white to gray/red
over the past 4 years, i have put several new DPFE sensors in this truck. It used to keep the ses light off for several months in the begining, but then it started coming back on sooner and sooner. The current DPFE sensor kept the light off for about 1 day, just long enough to get it through inspection. I'm wondering if it has something to do with the CAT converter being restricted or something.
The sensor I have now could be bad, but at $60 a pop I always wait til its time to get it inspected before I buy a new one. Every one that I buy works for a little while then when the light comes back on, I remove the sensor and it has water in it. Thats why I'm wondering if the catalytic converter is bad.
Yep, 100% genuine plastic.
The truck runs pretty good for 192,000 miles, but I have noticed that I cant run 87 octane anymore, or I get pinging under accelleration. 89 or higher and its fine.
I guess I'm just gonna leave it for now. In March when the inspection is due, I'll buy another sensor and hopefully It'll get me through inspection. I just dont know what else to try at this point, that isnt gonna cost a bundle of money.