po402 code Help?

[96 Windstar gurl]

Can anyone help me with a po402 problem???

[olopezm]

P0402: Excessive EGR flow detected.

This code might be due to a stuck open EGR valve or a bad DPFE sensor, I don't know if you have someone else you can borrow the dpfe sensor from, Ford is know because of bad dpfe sensors, so I would advise you to borrow the sensor from someone else and make a test on your windstar, if that doesn't solves the problem, then it will definitely be a bad egr valve.

What engine size do you have? 3.0 or 3.8 liter?.

If you have the 3.8 here's a picture about the location of the EGR and dpfe, thanks to wiswind for the picture:
http://rides.webshots.com/photo/1201...11220610tfjrRI

Best regards,

Oscar.

[wiswind]

I just answered your IMRC question.
THIS code is a bit more critical as it can cause the motor to run rough and/or have more emissions.
I would address this issue first, then see if the other issue is still present after this has been cleared up.

You might get lucky with the IMRC code.....I had a IMRC code come up only 1 time, and it was when my Vehicle Speed Sensor (VSS) went out.
I got the speed sensor replaced, and never saw the IMRC code again.
I am guessing that it was caused by the rough running issues that I was having due to the speed sensor.

P0402 EXCESSIVE EGR flow is not as common.
Low flow code is very common on the Windstar for a variety of reasons, including clogged EGR ports in the lower intake manifold.
However, that would not cause excessive flow.

The EGR valve on the Windstar is not known for having any problems, not that it is not possible, but it is not common.

I would recommend that you inspect the EGR tube for any signs of holes.
Inspect the hoses that connect the DPFE to the EGR pipe.
The EGR pipe goes from the FRONT exhaust manifold to the EGR valve.
The EGR valve opens, as controlled by the PCM (computer) by controlling the vaccum to the EGR valve.
The PCM directs vaccum to the EGR valve to open it.

No vaccum to the EGR valve, it will not open, and there will be NO EGR flow.
For this reason, Excessive EGR flow would not be caused by a disconnected vaccum line to the EGR valve.

The EGR tube has a restriction in it, located between where the 2 hoses for the DPFE connect to it.
Because of this restriction, as the flow through the EGR tube INCREASES, the pressure drop across the restriction, will increase.
This causes the pressure in the top hose to be less than the pressure in the bottom hose when there is flow, the amount of flow can be determined by this pressure difference.
This difference in pressure is measured by the DPFE which converts it to an electrical signal that indicates how much flow there is.
This signal is sent to the PCM, which can then control the EGR valve to obtain the correct amount of EGR flow.

The DPFE is a common failure item and it not hard to change.

Here is a link to a picture that shows the location of various EGR components on the 1996 3.8L windstar motor.
The EGR tube is covered by a shiny metal braded material.
http://rides.webshots.com/photo/1201...11220610BGkBnV

[olopezm]

Originally Posted by wiswind

P0402 EXCESSIVE EGR flow is not as common.
Low flow code is very common on the Windstar for a variety of reasons, including clogged EGR ports in the lower intake manifold.
However, that would not cause excessive flow.

The EGR valve on the Windstar is not known for having any problems, not that it is not possible, but it is not common.

Just in case, I only meant to say that bad DPFE sensors are common in ford's history, not that the EGR valve or anything else are common problems

Best regards,

Oscar.