P0402 code on a 1996 4.0

[Bob Mayo]

My Explorer just turned on the check engine light with a P0402. I looked it up and it says EGR flow excessive. A little history first. About a year ago I had a P0401. It turned out to be the DPFE sensor. I replaced it and the error disappeared for a while. A few months later it returned. I took the sensor back because it has a one year warranty. The replacement worked fine. Now its another few months and P0402 seems to be related to the P0401. Could this sensor be bad again? I think it is still under warranty. Thanks.

[Bob Mayo]

It turned out to be the DPFE sensor again. I replaced it under warranty for a second time.

[shorod]

Somewhere I read about certain DPFE sensors to avoid, such as avoid the aluminum and go with the black plastic ones, or vice versa. That's unfortunate that they are failing so often for you, but at least it's still under warranty and easy to replace.

-Rod

[way2old]

The new version is the plastic one. Aluminum was original. You might want to check out the wiring also to see if there is a wiring concern. It is a good possibility the sensor is bad though.

[Bob Mayo]

You are right. The new one is plastic. It came with a write-up saying that this is the new and improved sensor. It's from a big name company that I trust. I read somewhere that these sensors are prone to damage from moisture by their design. I did not find any moisture in the hoses or in the sensor. I would have liked to have opened it up to check further but then the warranty would have been voided. The connector looks clean with no frayed wires. - Bob