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P0401 Insufficient Flow To Egr


Andrewsreef

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This is my latest problem and appears to be a EGR problem. I looked at Alldata and it can be one of three parts. Does anyone have any experience with this problem on a LX450?

I am tempted to change the Valve myself and save the trip to the mechanic. It is easy to get to and not to expensive.

Thanks for the help.

Andrew

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Andrew,

I've been dealing with an intermittent P0401 since I bought my truck last September. It will come on for a couple of days and then go off for a few weeks/months. I tried going through the FSM testing procedure (checked the EGR Modulator and removed and tested the VSV to EGR), but didn't come up with any conclusive failures. Since mine is intermittent, it may be hard to detect an error. I went ahead and replaced the EGR modulator, because it's been said that the stock one (green cap) had known problems and it has been superceeded by another one. Thought it was worth a shot and probably needed to be changed anyhoo. Didn't help. My next step is to replace the VSV to EGR. The shop quoted me $250 to replace it when I first bought the rig. I think it's about a $75 part, and now I can pull the throttle body and have it swapped in 30 to 45 mins. After that, I'll probably look at replacing the EGR. I hate thowing parts at it but I can replace a lot of these for the same price the shop was going to charge for the VSV.

BTW, P0401 is a pretty common problem, and I think frequently it has been the VSV. As with most of these emisions type problems, it doesn't take much to throw a code.

Rookie

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Thanks for the info. I went ahead and ordered the parts from Toyota. Cost me $300 for all 3. I am going to try and replace them all this weekend. All look easy except for the VSV. Where is this thing? I heard in another forum that you could remove the support bracket for the Intake and get to it. I see a vachume module of some sort directly below the intake but I am not sure this is the VSV. It figures the most common problem part would be the one impossible to get to.

I am anxious to replace these parts on mine as I have been having problems with pinging even with 93 octane gas. I have heard this can be a problem to cause knocking.

Thanks for the info.

Andrew

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The VSV for EGR is located underneath the air intake chamber. It's pretty easy to get out once you've removed the throttle body. I've heard of someone getting to it by removing the intake chamber, but I haven't done it that way. I'd recommend taking off the throttle body, that way while you've got it off you can give it a good cleaning and blow out all the lines. If you've got the FSM, the first time through this is an hour and a half to two hour job, and the next time you will be able to do it in 30 minutes. I would get the FSM if you don't have it. I see too many people winging it, and they end up taking off and !Removed! up stuff they didn't need to (.

:cheers:

Rookie

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I am definately going for the manual. My Alldata is useless for this kind of repair. What is really bad is the mechanics around here do not use them and they end up wasting my time and money doing the wrong thing (like spending all day trying to get the fuel filter off).

What is involved in taking off the throttle body? I am trying to get a hold of a manual real soon.

Thanks for the info.

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Rookie, according to the FSM, do you have to drain the coolant to remove the Throttle body? Alldata says you do in the process and that seems odd to me. I would hate to waste my coolant as that was just serviced.

Thanks for the help.

Andrew

The FSM indicated to drain the coolant too, but it is not necessary. There were only a few drops that came out when I disconnected the small water bypass hose. I had the same question before doing mine, and this response was consistant with what others experienced. Don't know why the FSM indicates to, but it does that sometimes.

If you need the proceedure, e-mail me your fax number, and I'll try to remember to bring it to work tomorrow.

Cheers,

Rookie

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Rookie, thank you for getting me that info. It is very much appreciated. The VSV cost me Just under $100 with tax. I am getting no deal from the dealer. My Wife's Cousin owns a local tranny shop and can get me a discount on parts but I hate to bug him.

What I plan on doing is replacing the EGR and the modulator and see how the truck drives/acts. I do have the old green top modulator so I may be in luck. If I am still having CEL and pinging issues, I am going to attempt the VSV on Saturday.

THe info in the FSM is much more detailed than Alldata and your notes are a BIG + but I am a little nervious about doing the VSV. I may get a friend of mine to help with it if he can. My luck I will brake the Throttle body or something else quite costly.

Again, thank you so much for the info.

Andrew

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Your welcome.

Don't be to worried about the throttle body removal, it's not that big of a deal. I put the notes on there just to give you a heads up on a couple of things, not to scare you. The whole setup is pretty stout, just don't tear at it like a gorilla is all. Just take you time and use your common sense, and you'll be golden.

I doubt that your pinging is related to any of the above. I too get some slight pinging under certain load conditions such as pulling a hill when in low gear. It pings a couple of times before the knock sensor (I guess) kicks in. Not sure what the deal is. My timing is set at the factory recommendation. I may end up retarding it a half or full degree and see if that helps. I'm running 89 octane and don't plan on going to 93 because it's (the pinging) not really happening much. I take it your timing is not advanced?

Anything ever happen with your head gasket issue?

BTW, I get all my OEM Toyota parts from a guy named C'Dan with American Toyota on the IH8MUD site. His prices are excellent (for comparison, the EGR modulator you just bought cost me $45, no tax, no shipping cost) and he's a great guy. You might try lurking over there some, you'll learn a lot more about your rig there. This site is fine, but the folks here are more into sound systems and DVD's, than busted knuckles and dirty finger nails (no offense). Also you can run a search on pinging and see what comes up.

Cheers,

Rookie.

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Thanks Rookie, I do not seem to be getting the CEL anymore so it may be ok. I will definatly check out that web site as I am at a loss.

The Headgasket or what ever my seeping leak was my mechanic put some stuff from Cheverlotte into the radiator and it has not leaked since. Kind of scarry, huh. Supposed to stop the electrolisis that eats the gasket???I have alot of issues with this truck and if it does not get better soon, it will go by by. I wanted one of these things forever but this one has been a total frustration.

Thanks

Andrew

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Rookie, thanks again for the fax the manual and your NOTES were invaluable to repair this. I did it Sat AM with little problems. The CEL is now off so I hope I am ok. THanks also for the other website information. Unfortunately after talking to them, I need some serious help with my truck, Headgasket is down the road and I need to get my Birfields repacked. Still not sure if I am going to keep this thing. Another thing I noticed while doing this repair, one of the nuts that holds the intake together has been overtorked by someone and cracked the intake at the part where the screw goes in. Not sure if this can be repair with the headgasket or if it needs to be replaced. More $$ I am sure.

THanks again.

Andrew

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Glad it helped. Now I bet you can do it in under an hour right? It's all about learning it. After you've done it once, you're a pro.

Take your time figuring out the birf. thing. The MUD site has all the info. needed, you just have to sift though to get your game plan together and all the parts on hand. It took me a FULL weekend, but I somewhat took my time, and you always run into some snags here or there. You may check around on the site to see if some folks in your area a interested in getting together for a birf. party. It always helps to have extra hands and minds around.

I ordered the VSV from C'dan today and hope that will get rid of my P0401 and slight pinging. This week the CEL in not on, but it will come back until I fix the problem.

As I mentioned, the intake parts are aluminum with low torque requirements. Some jag-off got in there and over torqued them. If you look at one of the threads floating around right now on the MUD site, there's some dude on ebay parting out an 80. You may be able to pick up the intake manifold for pretty cheap. Check with C'dan first to see what his new price is so you don't over pay.

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That sounds pretty good, but I honestly don't have a feel for what those things would go for. I might call a local Toy. dealer and find out what they list for. Typically C'dan's prices are 25% below list, along with the fact that it's free shipping for orders over like $75 and no tax. Of course my local stealer is typically 10% above list.

I would also go ahead and get an FSM so you can do this job yourself. I don't think it's to bad. I bought the 97 Land Cruiser manual since all the primary mechanical stuff are the same. Most of the differences are in the creature comforts. A smart shopper can get it new for $65. Even if you decide to sale your rig, you can sale the manual on ebay for that easy.

Cheers,

Rookie2

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  • 2 months later...

Rookie,

Did you do your VSV replacement yet? If so, did that go as planned? Did it take care of your pinging? I noticed you mentioned you got yours from C'dan; are they factory and C'dan is a distributor, or are they considered aftermarket through them?

Thanks.

jsmith8918

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Rookie,

Did you do your VSV replacement yet? If so, did that go as planned? Did it take care of your pinging? I noticed you mentioned you got yours from C'dan; are they factory and C'dan is a distributor, or are they considered aftermarket through them?

Thanks.

jsmith8918

I can tell you I replaced all 3 components and still had pinging. Espacially at normal acceleration. What I found out was there is a port about as big around as your pinky finger. This port is on the intake plenium and is accessable only after you have removed the throttle body. Mine was completely plugged with carbon. My CEL went out when I replaced my VSV but this port was the cause of the pinging.

Hope this helps.

Andrew

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Rookie,

Did you do your VSV replacement yet? If so, did that go as planned? Did it take care of your pinging? I noticed you mentioned you got yours from C'dan; are they factory and C'dan is a distributor, or are they considered aftermarket through them?

Thanks.

jsmith8918

jssmith:

Yes, I replaced the VSV for EGR about a month or so ago. No CEL (P0401) since, so I hope take has corrected that problem. Replacing the VSV isn't very hard after you remove the throttle body. Cruiserdan is a parts manager for Toyota American and all their parts are original new toyota equipment. He's owned a 93 cruiser since new and does his own wrenching, so he's about as knowlegable of a parts guy as you'll find in regards to landcruisers. Besides being a heck of a guy, he's very helpful, so you get what you need, not just what you ask for (if that makes since).

FWIW, I didn't expect for the new VSV to correct my pinging. I did a couple of other things, adjusted the TPS and added some Redline total system conditioner. My pinging was very mild and sparatic, and now it is moreso... meaning it doesn't or maybe I hear a light ping or two ever once in a while.

Hope this helps.

:cheers:

Rookie

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  • 5 months later...

Well, here's the update for me: I finally got my P0401 to go away. When I bought my LX450 (used with 100,800 miles on it), the previous owner provided a slip of paper from the dealer showing that they had diagnosed my P0401 and came up with a recommendation to replace the EGR Vacuum Modulator. I did that myself (piece of cake), but unfortunately that only made the P0401 go away for a few days. I then removed and tested and cleaned the EGR valve itself (a little bit more involved), but same results. I finally replaced the VSV for EGR and the CEL has been off since then (about five weeks now so far)! (Just in time for my state-mandated smog test, too!)

I chose to replace mine by following the directions in this thread recommending removing just the Throttle Body rather than the whole Air Intake Chamber Assembly, and that was some good advice! The job was easier than I had anticipated even though I took my time to replace every vacuum hose I could reach and clean everything I could get to while I was at it. Sure enough, once I got the VSV for EGR off and tested it per the test given in my Lexus Repair Manual, it failed so I feel confident that was the primary culprit all along. (Although, thinking back, I do recall the EGR Vacuum Modulator also failed, so maybe I had two culprits. Hmmm.)

A few hints from my experience: when I went to the dealer to buy the VSV for EGR, they were able to pull up the two different VSV's that are both located right in that area: the VSV for EGR and the VSV for Fuel Pressure Control. Unfortunately, their computer didn't give these descriptions to those parts. All their computer said was "VSV" for one of 'em, and "VSV" for the other one as well! I had to actually point to the upper one on the screen and say, "It's that one." And no, they are not the same.

To sum up, I thought it only proper to post my update here, and I want to thank you guys for giving me the information I needed to dive in and finally get rid of my P0401.

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By the way, Rookie, do you have a contact phone number or email for C'dan (Cruiserdan at Toyota American) that you could provide? I'm ready to tackle a few more jobs on my LX450 and need some parts.

Thanks.

Congrats JSmith. Glad to hear you got it taken care of. You can reach Dan at American Toyota at 1-800-432-6668. BTW, I think orders over $75, they comp the shipping charges, so I usually wait until I've got a few things I want to get.

:cheers:

Rookie2

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