EGR and Scan Tool Questions

[troverman]

I have a '96 2WD Limited with the 4L OHV. It has 133k on it. The vehicle sat for 5 years, being started and run periodically, but never driven. It has been registered and is going to be driven again. Being a '96, it must pass an OBDII emissions test here in NH. Previously, the MIL was on and the code was for EGR insufficient flow. I did not do any research and simply replaced the EGR valve. I cleared the codes, and just letting it warm up in the driveway, no MIL. Now there is a MIL P0402, EGR excessive flow. I know now this has been covered here, it would seem the DPFE sensor is at fault.

Before I spend $75 at AZ, I would like to know for sure. I have read to apply vacuum to the EGR while the engine is idling, if it starts running rough than the EGR is working and there is no blockage. I have also read a scan tool can monitor the DPFE reading, and if it does not change when vac is applied, than this verifies the sensor is junk.

I have an Actron scan tool, it can graph data, read live datastream, even do Ford 'special' tests.

I don't remember seeing a PID for the DPFE sensor. Is it one of the Ford special tests? Does anyone know what the Ford special tests do? (On the tool, they are listed like $$6 or something like that).

 

[Dilbert5]

According to Alldata, you can use a hand help vac pump to apply vac to the sensor and monitor the voltage with your scan tool. here are the values you can expect.

in hg voltage
8.83 4.6
6.62 3.54
4.41 2.61
2.21 1.58

 

[marragtop]

I suspect the dpfe sensor, but any testing you can do will help trouble shoot. When you replaced the EGR valve, were the vacuum lines clear?

 

[fixxxer]

A P0402 DTC indicates that self-test has detected EGR flow, possible causes:
no-seated EGR valve
Damaged EGR valve
Damaged EGR Valve Position (EGR VP)
Plugged or pinched EGR valve vacuum hose
Plugged or iced EGR Vacuum Regulator (EGR VR) Solenoid vent
EVR circuit shorted to ground
Damaged EGR Vacuum Regulator solenoid
Damaged PCM
Check for presence of DTC P1409

 

[troverman]

Replaced the DPFE sensor for $65 at AZ. The old part was aluminum, the new is plastic. Driven about 100 miles, no check engine anymore, all the monitors have cleared. Guess that was it...