Help With Vacuum Leak

[mranderson214]

Hey Everyone, I was wondering if anyone can help me with this problem I am having.

I have a 2002 Explorer, V6 with about 150,000 miles on it. I also have the infamous "Service Engine Soon" Light on my dashboard.

So I got the codes checked at Autozone and some other places for free. I tried a few different places just to be sure that I had the correct data. Basically, I am getting two codes (one of which I think is triggered just because of the other).

My two codes are: P0402 and P1131.

Now, ill tell you guys what I got done to the car since these codes popped up. I got a new EGR valve put on and I got one O2 sensor changed. The O2 sensor was replaced with a new one. It was the drivers side O2 sensor located after the Cat. Converter. I also keep up on my Oil changes and tune ups.

The car runs fine and if I didnt have the CEL on my dashboard, you'd swear nothing was wrong with the car. Occasionally, I get a slightly rough idle when sitting at a red light or when coming to a stop.

I do not know what to check exactly seeing as how one code is telling me that the EGR slow is excessive or lean, which is know is highly unlikely with a new EGR valve put on..

So what do you guys think? Maybe one of the other 3 O2 sensors need to be changed? or all 3 of them maybe? Is this an intake manifold problem maybe? I've read that the PCV Valve hose has a lot of pressure and they are prone to punctures and such. I tried to look for my PCV valve but I am not sure where it is on the 2002 V6 engine. I think have an idea where it should be but its hard to get to. Are there any places that are common for these types vacuum leaks on this particular model car?

One thing I might want to point out is that upon checking my vacuum hoses, I came across one that was a little dry and slightly flimsy. It was not cracked or punctured to my knowledge, but it was weak. I think it says Fuel on it or something. It runs from the passenger side, near the EGR behind the engine, and to the drivers side into a round plastic module of some sort (to the left of the high voltage fuse box).

Any advice you guys can give would be greatly appreciated. I do not want to pay someone any more money for them to misdiagnose my problem, so I am hoping someone here could give me some things to look at/check. Thanks in advance!!

 

[Javadog123]

When you did the egr, did you clean out the connected lines/openings? Things can get ugly in there. As far as vacuum leaks, start the engine and then spray different lines with carb cleaner or starting fluid. You will hear it if you hit a vacuum leak.

 

[mranderson214]

Thanks for the reply.

I had the EGR lines cleaned when the new one was put on. A new gasket was put on with it as well. And is there any areas that the carb cleaner doesnt have an effect on? because I tried spraying the lines with the engine running but i didnt notice any difference in the engine. Like i didnt hear it rev up. I will try the spraying trick again, but my fear is that it is a crack or something wrong in the intake manifold. How likely do you think that this is the case?

Thanks!

 

[sethmorgan]

See if this helps: http://www.obd-codes.com/p0402

 

[esclamada]

I have the same problem before, did you replace the EGR sensor? and the vacuum hoses? when I have a vacuum leak due to faulty hose it triggered a lot of codes. I didn't replace the 02 sensors or the EGR valve since they're OK.

EGR sensor:
http://www.facebook.com/media/set/?set=a.124551497613010.20512.110528882348605&type=1


VACUUM LEAK:
http://www.facebook.com/media/set/?set=a.124126220988871.20343.110528882348605&type=1

 

[mranderson214]

thanks for the replies guys. i did not replace the EGR pressure sensor but it seems that that would be something logical to replace. so do you think that the pressure sensor would cause rough idle every now and then as well?

 

[esclamada]

that might help since it will clear the CEL. If the rough idle still continues, you have to check for vacuum leaks first, then clean the MAF, then the IAC (, skipping EGR valve since you bought new) and throttle body. Do it one at a time if there are improvements.
was your PCV changed at 100k?



IAC Cleanup:
http://www.facebook.com/media/set/?set=a.142692505798909.29033.110528882348605

 

[mranderson214]

ok thanks. ill give those a try and try it one by one. and im not sure if the pcv valve was changed at 100K miles. i brought the car used at a little over 130K. i heard the pcv valve hoses are prone to breaking under normal wear and tear. i was never actually able to find the pcv valve or its hose on my 02 V6. any ideas where it is, because i checked the forums but i only saw threads for the V8 engine.

thanks!

 

[swetrid]

P0402 is dpfe sensor

 

[sethmorgan]

On the 4.0 engine, the PCV valve is located at the rear of the drivers side valve cover facing the firewall. It is connected to the intake manifold via a large hose about 6 inches long. Reach back there and you will feel it. The hose just slips off, it has a piece of foam insulation around it. The PCV valve unscrews in about a quarter of a turn. It will make sense when you start feeling around back there. Replace with Motorcraft only!

 

[esclamada]

http://www.explorerforum.com/forums/showthread.php?t=310053

 

[mranderson214]

thanks for all the suggestions guys. I will give all of the suggestions a try. im leaning towards it being the DPFE sensor for the EGR because i got it rescanned today and the P1131 code for the O2 sensors disappeared and now only the P0402, EGR flow excessive appears.

My mechanic believes that it isnt the PCV valve because the hose is intact and he said that i dont need a new one just yet. so he recommends that I change the DPFE sensor and I hope that does the trick. Thanks for all the help everyone

 

[sethmorgan]

One way to check that the PCV is NOT working is to take if off and shake it and if it doesn't rattle, it's NOT working. Now, just because it DOES rattle doesn't mean it IS working, so keep that in mind.

 

[mranderson214]

Thanks for all the help everyone. It seems as though it was the DPFE (EGR Pressure Sensor). I changed it yesterday and it cleared the light. It hasnt come back on since then and I drove about 30 miles already. I hope this is the end of my CEL Problem. Thanks all!!!

 

[sethmorgan]

Good news. thanks for the update.