Hi, my son has a code p0402 on his ford ranger. I am trying to find out what to look for in fixing this problem. the code is an Exhaust gas Recirculation Flow Excessive detected. hope someone can enlighten us as to the problem and how to fix it. thanks (sorry i am a brand new member so please bear with me) thanks again cp

 

i feel bad that nobody's replied. i have no idea how to fix it though sorry =(

maybe this bump will get someone's attention.

 

P0402 is for excessive EGR flow detected.

It could be a few different things but the odds are 99% that it is a bad Differential Pressure Feedback EGR sensor, the sensor that measures the EGR flow rate. The DPFE sensors were very unreliable around 2000~2001 and most end up getting replaced. Approximate price for the part is $40~$60 and it is not difficult to change.

The background in this picture is not a Ranger but the Ranger DPFE sensor looks the same.

 

so just pop the old DPFE off and replace with a new one?

 

yeah....

 

alrite, i replaced the sensor, but my check engine lights still on, do i need to have it cleared or is something else wrong???

 

You can take it to autozone and they will read and clear the code, or if you disconnect your battery for a little while, it will reset itself as well. I think 30 minutes is the time frame needed...

 

autozone can and will read /clear it
as far as the battery, you really only need disconect for a few minutes

 

To clear your computer very quickly after you unplug it from the battery, just tap your brakes. The rear lights willl try to light up draining it. edit: draining any excess energy in the system, not the battery.

 

I just got the same code today. Apparently Ford's DPFE sensors have a reputation of going bad regularly. Ford has even told techs not to bother even diagnosing if a P0401, P0402, P1401, or P1402 is stored, and to just replace the DPFE sensor. But the problem could also be that the EGR valve is sticking. The valve itself looks like this:

It's located at the right rear corner of the intake manifold, near the firewall, next to the DPFE sensor.

 

03 Ranger 4.0's don't have EGR. Fortunately, I've never had to replace a DPFE on any of my own vehicles.