Finally got my 4runner back....but a code 71....but without the symptoms??
 

Well I finally got my 4runner back. It runs perfect, idles just great, and all that good stuff. BUT my check engine light came on about half way home today. Code 71 - EGR malfunction thing. Funny thing is that there are no bad symptoms of a bad egr valve. Lots of power (for a 3.0), perfect idling. My mechanic said he was having troubles putting all the vacuum lines back in the right spot so im thinking that might be it.

My questions are:
1.) Does anyone have a link to the vacuum line routing?

2.) Will my 4runner get messed up if I leave the check engine light alone with my egr valve "malfunctioning"? Will it be alright to drive or should I leave it alone until I can get it off?

3.) Is there any way to check and find out exaclty what is causing what problem? (well thats kinda vague)

There is a big sticker on the underside of my hood that shows the vaccuum line diagram. Maybe yours has one.

Nope, the underside of my hood is bare. Actually its flaking, haha.

I had an intermittent 71 code. Dealer said it was reversed vacuum lines, charged me almost nothing to find the problem. Just after I bought it (from a private party), had no time to troubleshoot it myself, as I needed to do a smog test to get it registered. One possibiity.

Here maybe this will help, I hope so, it was pouring down rain while I took this.
http://i38.photobucket.com/albums/e1...7/IMG_5167.jpg

Well, I reset my computer and the cel went off for about 20 miles, and then came back on again on the way home. My 4runner is running in top shape so should I be worried about the light? Nothing seems to be wrong with my 4runner, but i dont want to hurt anything driving it with the light on. What you guys think?

Mine has been showing the same code 71 for about month and a half, so far I dont think its affected anything....yet. And its also running perfect. Im going to take mine to a mechanic to see what they come up with, Im stumped.

Only thing that I can think of is what Richard said. That one of the vacuum lines are reversed. I collected a bunch of links and im gonna go through my vacuum system this weekend and check everything out. Hopefully ill spot the problem. If not, there are a few other things to try. If all else fails, im just gonna block the egr valve off and put a piece of tap over the light.

Gas cap on tight?

code 71 also means the EGR sensor isnt heating up in a amount of time, THe sensor is where the 2 wires are coming out just below the EGR dashpot, Make sure that plugged in right first.

The top of the engine hoses are easy to figure out, they follow eachother from the throttlebody to the hardend lines of the throttle linkage and again to the hardend lines at the front of the engine, From there they go soft and connect to that black plastic round valve at the front left side of the engine.

while standing and looking from the passengerside fender tword the engine and looking at the green VSV, The hose fron the top of the VSV (closest to you goes to the bottom of the hardened hoses coming out from under the plenuum closest to the EGR dashpot, The outlet of the VSV goes to the hardend hose just above where you put the other.

5 things can go bad on the EGR setup.
The black disk valve, It can get plugged with carbon and water and cause a CEL. (WD40 and carbcleaner can clear it out but not always)
The vacuum hose passages on the Throttlebody can become plugged (Carbcleaner through those)
The EGR dashpot can get stuck or have a hole in the diaphram (while engine is running put a vacuum on the hose atop the dashpot (just suck on it), If the engine stalls or almost stalls its clear and working, See if it will hold a vacuum, This will tell you there is a hole or not)
The Green VSV on the passenger fender can become plugged or burnt, Hmmm, How to explain how to check if its working, I think at idle its powerd so you can unplug it and make the connections just touch and hear or feel it clicking or use some jumpers from the battery to power it.
Mine was plugged at one time and I used WD40 and carbcleaner to clear it out.
The 5th is rare but it does happen, The thermister on the side of the EGR body (the 2 wires that come out) can go bad, What this does is sence the exhaust heat up to a point , If it doesnt heat in a curtain time or the temp goes down below a curtain temp durring nomal running it will CEL, This is also what calls the CEL for the other EGR devices going bad.

There is a resistor that was used in no smog check states and can be used to fool the ECU into not giving EGR CEL's, but I suggest fix the problem.

:good: Thanks man!! I'm goin at it tomorrow so i'll let you know how it goes. Prepare to get some PMs and pictures tomorrow. Just a quick check over it today shows one or two vacuum lines unplugged. Hopefully I can get this fixed tomorrow.


OOOO and my transmission is starting to slip :bang:

My problem was that one of the vacuum hose passages clogged. On the Vacuum Hose Routing Diagram, it is the one that goes from the throttle body port E to the EGR-Vacuum Modulator port P. Inside the second stage(count from the throttle body toward the modulator) of the hardened or metal line was the problem; I can't blow through it. I believe it was the moisture from the modulator became dried and clogged the line. I cleaned it with carb and use a flexible metal rod to push through it and then blew it with compressed air. And the CEL does not come on again after that.

I was having an intermittent 71 code thrown and what I found that fixed it was that same exact problem, so far no more 71.