Engine Code Help Please - Code P0402

[Johns96XLT]

I have a 96 Explorer all stock with a 5.0 engine with 93K miles.
I threw a code the other day:

P0402 - Exhaust Gas Recirculation Flow Excessive detected
Dead Link Removed

I cleared it out and it has not come back yet. It has been about 2 days. I have not noticed any performance issues or anything else.

I did a search, and all the threads seemed to have other codes along with it. This is the only code I have.

Can anyone give me any tips on where I should start to fix this? Should I even worry about it at this point?

Any help appreciated,
John

 

[Lemondrop]

Getting same code out of my 96 5.0 . It's the EGR valve located on the rear of the intake by the fire-wall . The plunger for the EGR valve travels through the metal base of the valve and gets scored up . When it tries to close it sticks a little and pops the code . It will get worse and happens on my X when I slow down for a traffic light / stop,etc.

Autozone sells the EGR vavle for 99 bucks . Carparts.com has the valve for like 66 bucks . There are coupons for free shipping or 10% off your order and the valve is like 7.40 to ship so the free shipping is better than 10% off 66 bucks

I guess it sounds like I have gone to buy this valve a few times
I just hate buying it when I know mine really isnt broken , just sticky . I also lost a O2 sensor but thats a different story .
Id buy the valve from carparts.com since it's 30 bucks cheaper than Autozone,etc. .
Don't forget the gasket too , I bought a gasket from Ford and they gave me a 1 hole gasket that is wrong . Dunno if they screwed up or what but it's a 2 hole gasket . The 96 5.0 is a ******* for parts as during the half way point or so of the year most of the parts change .
I removed my valve and cleaned it and lubed the plunger shaft , but I could see the scoring and knew it would bring the CEL back on soon . Last about 3 thousand miles on the re-lube before the CEL popped back on .
You might wanna get a 9/16 and a 1/2 inch STUBBY wrench(s) to get the valve off and on . Regular lenght wrenchs are a bit hard back there . But it's cheaper to buy stubbies than to take the X to a shop for a 2 nut EGR valve change

 

[Johns96XLT]

Thanks Lemondrop.

Any other ideas, or is this the next project I am stuck with?

 

[dduk]

My EGR valve was stuck open (due to corrosion) causing the engine to run extrememly rough. I just removed the diaphram and forced the valve closed. I throw the EGR CEL, but now I get 5-10% better fuel economy, more power, and I should get improved engine life. Not too good for emissions though.

 

[Lemondrop]

Originally posted by dduk
My EGR valve was stuck open (due to corrosion) causing the engine to run extrememly rough. I just removed the diaphram and forced the valve closed. I throw the EGR CEL, but now I get 5-10% better fuel economy, more power, and I should get improved engine life. Not too good for emissions though.

Actually if your EGR is not working at all , it can shorten your engine life
The engine timing is set up with the EGR in the air fuel mixture map . That is why you have more power ,etc. Only problem the EGR will cause is pinging , when its disabled . The pings can do bad things to your pistons

If it's isnt pinging then Id say your gonna be fine .

 

[dduk]

Hmmm. With more oxygen getting in the pistons, I can understand the increased risk of pre-ignition. As of yet, I have none in my Ex. As long as no pre-ignition occurs, the engine life should be increased.

 

[Elk_hunter]

Had same problem last month at this time. I changed the DPFE sensor(Pressure feedback sensor) little 3 x 4 in box that is right below your IAC valve. Fixed my problem

 

[Johns96XLT]

Well, I went to Auto Zone. I got the DPFE sensor.
They didn't know what I was talking about, but they found it and I got it.

It was only $5.00 cheaper than the EGR itself so I hope this works. I'll be putting it on this weekend.

I haven't even looked under the hood yet, my wife has been driving it. Does anyone have pictures of where it is located?

 

[Science Guy]

I would check for a disconnected vacuum line (the one that goes to the EGR valve). If it is accidently disconnected the valve does not function and gives the code you mentioned. I would look there first.

 

[johnhanson]

I would appreciate a reply from any of you guys. My '96 5L tripped the CEL and I got the P0402 code too. This has been a problem for 8 or 9 months (ok, I'm slow.) Frankly, other than starting rough, the truck runs fine. By the way - Autozone checks the codes for free - you don't have to buy the code checker. Getting advice, thinking about it, and looking at my Haynes manual, I figure A) bad EGR valve, B) PFE sensor (not DPFE, according to Haynes) or C) Ox sensor. So far, I've only tried the PFE. The ford dealer tells me its the sensor right on top of the EGR valve but I'm not sure this is right. No vacuum hoses going to it. Does this seem right? The 5L is apparently different from the V6 vehicles. Anyway, no change - CEL still comes on. So... how hard is it to swap in a new EGR?..

 

[Johns96XLT]

bump.

 

[Lemondrop]

Did the sensor fix your truck John ?

Or are you going to replace the EGR valve also or anything ?

 

[Johns96XLT]

I've been too lazy to try it.
I don't really see an easy wasy to do it. I haven't gotten a Haynes or Chilton book yet either, just the parts.

It looks like I have to remove the intake hose, and the throttle body and more to get back there. I'm really not looking forward to it.

Oh, plus the code has only showed up once since then. And it disappeared on its own???

 

[rickhopk]

P0402

Check the voltage on the EGR position sensor at the back of the EGR valve.

Insert a straight pin (fiine sewing needle) through the orange yellow wire at back of sensor. With key on (engine off) and a digital multimeter connected positive to the pin and negative to ground the meter should read about .40 Volts.

Use a Vacuum pump to open the EGR valve and the meter should read 3.9V.

If the readings are within 15% of thbe above numbers the EGR valve and sensor are probably good.

If the reading is .7 or .8 volts with the EGR valve closed then you can try cleaning the EGR valve or replacing it.

If you replace it with a new one, make sure the reading is within 15% of .40 volts. If it isn't, file off the end of the position sensor rod until it is around .40 volts.

Use high temp silicon sealant to plug the hole made in the wire after you remove the pin.

You can also check the sensor by removing it.

The resistance between the pin with the brown white wire and the pin with the orange yellow wire (the sensor, not the connector) should read about 5,000 ohms extended and 100 ohms pushed in. Mine read 3120 ohms extended and 68 ohms pushed in and was very close to a new one which I tested at the shop.

Contact me if you need some more diognostic info

 

[rickhopk]

P0402

One other thing, you can remove the EGR valve with a set of S shaped box wrenches. Just be patient with the lower nut and use a mirror. The upper nut is larger than the lower one (I can't recall the exact sizes). You do not have to disassemble any engine parts. Have a magnet handy since you may drop one of the nuts

 

[Johns96XLT]

Thanks for all of the help and suggestions guys.

With all of the Ford incentives going on and X-Plan pricing,
I am now the owner of a 2002 Explorer Sport Trac
Needless to say, I don't have to worry about EGR codes anymore.

Thanks,
John