EGR

[jimn411jm]

Can I delete the EGR on my 2000 Mustang 4.6 and still pass Inspection? I have replaced several parts connected to the EGR and I still get a check engine light, I clear the code and a day or 2 later it pops back up. I also have a leak in the fuel evap system code but That is the grommet for the filler neck. Could that possibly be also caausing the EGR P0401 code? For reference the car sat for 3years . I just replaced the fuel pump and filter a month or so ago. Any help is very much appreciated

 

[wmburns]

Just wondering. Was one of the parts replaced the DPFE sensor? Did you double check that the two vacuum lines to/from the DPFE sensor are connected and leak free?

IF replaced, did you use an aftermarket DPFE sensor? Ford has changed the calibration of the DPFE sensor. Either buy a Ford supplied unit or use one made by a well known maker.

Finally did you double check that the EGR passage ways inside the throttle body aren't clogged with carbon? Consider taking off the EGR valve and throttle body to clean/check the EGR passage ways.

If you delete the EGR hardware the PCM will still throw a DTC code.

>>

P0401 - EGR Flow Insufficient Detected​ The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.​ Vacuum supply EGR valve stuck closed EGR valve leaks vacuum EGR flow path restricted EGRVR circuit shorted to PWR VREF open to D.P.F. EGR sensor D.P.F. EGR sensor downstream hose off or plugged EGRVR circuit open to PCM VPWR open to EGRVR solenoid D.P.F. EGR sensor hoses both off D.P.F. EGR sensor hoses reversed Damaged EGR orifice tube Damaged EGRVR solenoid Damaged PCM

 

[jimn411jm]

Changed the dpfe sensor. Bought it from Orielly's, replaced the egr valve , egrvr solenoid, All hoses went back on as removed and seemed to be leak free and its getting vacuum, Checked the passages and they also seem to be clear

 

[wmburns]

I'm going to assume that the P0401 DTC code is present even after all the above work was done.

Also wondering. Did you happen to notice that one of the "possible" causes is the reversal of the the DPFE hoses?

In general when working on my own cars I attempt to test first before replacing parts. If this were my car would start with some basic functional tests. For example using a vacuum hand pump to "activate" the EGR valve while the motor is idling. When vacuum is applied to the EGR valve the motor's idle should change. As the vacuum increases the motor should run worse and worse.

If so, this PROVES the basic EGR system can work when controlled.

If not, this PROVES that the EGR path is blocked or the EGR value itself isn't working. Obviously the next step is to figure out where's the blockage.

Once it is know that the EGR can work when controlled, then I would monitor the DPFE sensor to confirm that it responds to change in EGR flow. Here's where I think an advanced ODB2 scanner pays big dividends. Again using the vacuum hand pump on the EGR value while monitoring DPFE EGR flow, slowly increase the vacuum and note what the DPFE sensor reports to the PCM. Obviously the flow should increase as the vacuum is increased.

What to do next depends upon these test results.

Here's some information on a very affordable ($30) Windows based ODB2 scanner.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...

www.stangnet.com

Regarding the EVAP leak. Obviously all of the DTC codes will never go away until the gas tank is vapor tight.

 

[MustangIIMatt]

Just wondering. Was one of the parts replaced the DPFE sensor? Did you double check that the two vacuum lines to/from the DPFE sensor are connected and leak free?

IF replaced, did you use an aftermarket DPFE sensor? Ford has changed the calibration of the DPFE sensor. Either buy a Ford supplied unit or use one made by a well known maker.

Finally did you double check that the EGR passage ways inside the throttle body aren't clogged with carbon? Consider taking off the EGR valve and throttle body to clean/check the EGR passage ways.

If you delete the EGR hardware the PCM will still throw a DTC code.

>>

P0401 - EGR Flow Insufficient Detected​ The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.​ Vacuum supply EGR valve stuck closed EGR valve leaks vacuum EGR flow path restricted EGRVR circuit shorted to PWR VREF open to D.P.F. EGR sensor D.P.F. EGR sensor downstream hose off or plugged EGRVR circuit open to PCM VPWR open to EGRVR solenoid D.P.F. EGR sensor hoses both off D.P.F. EGR sensor hoses reversed Damaged EGR orifice tube Damaged EGRVR solenoid Damaged PCM

The EGR code can also be related to the Evap leak. Engine vacuum is used for both systems, so a large evap leak can cause insufficient EGR flow.