Hi everyone,

I have a problem on my 1999 Ford Ranger 3.0L (66,000 miles) with the engine light coming on. I took the truck to Advance Auto Parts and had them read the code. It came up with a p0402 - EGR Flow Excessive. I looked up the code on this site and came up with many issues with the EGR Position Sensor or DPFE being faulty. I bit the bullet and changed out the sensor which did have some corrosion and still have the same issue. I then tried to clean out the EGR Valve, replaced the gasket but still have the same issue. When the truck is in idle it sounds as if it is going to stall and it seems to come in cycles. When cleaning out an EGR Valve, is it necessary to clean other areas? I'm not an expert when it comes to cars but I'm willing to put the effort in to save money. I may replace the valve but I want to get some opinions as to what I should do next. Any help would be much appreciated.

BTW. This site is an excellent resource and kudos to the people responsible for maintaining/developing this site.

 

The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle.

The DTC associated with this test is DTC P0402 f
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 The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle.

The DTC associated with this test is DTC P0402  The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle.

Hope this helps.

 

From what your saying then is that there is a test I can perform to check the DPFE voltage? I've seen a test I can perform on the EGR Position Sensor located somewhere in this forum. Is this the test you are referring to? If not, what steps are needed to diagnose the EGR Valve? I'm not quite clear on your explanation.

Thanks for your help,

Paul