You can buy non OEM replacement parts but you will be harassed by the purists. If you call Sam at Lowe Toyota he will give you a mud discount with free shipping. That's the way I always go. HTH.
P0401 Defeated - with pics (1 Viewer)
- Thread starter Flank
- Start date
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You can buy non OEM replacement parts but you will be harassed by the purists. If you call Sam at Lowe Toyota he will give you a mud discount with free shipping. That's the way I always go. HTH.
If we are talking about the vacuum hoses, my local dealers have those in bulk and very cheap. Take a section in with you and they can sell you lengths that can then be cut to size. I would go that route. For all other hoses, especially the ones that are formed, I would also recommend calling or PMing Sam. He is great to work with.
Hey flank just finished cleaning the upper intake plenum (common block ports) and replacing all hose and parts on my egr system. Did u do a readiness ECM check after u did yours or just normal driving? Because iam still getting the P0401 code. Thanks
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #107
I have a scanguage, so I cleared my code and it never came back. Disconnecting your battery should clear the code as well. So question, did you have the code straight from start up, or did the light come back on? How did it run when you first started driving it? The engine will run a little erratic right at start up after work like this plus having the ECM cleared by disconnecting the battery, will have higher RPMs at first. As the computer learns the new tempo of the engine, it should settle down to normal. If you have a code right at engine start up, then the code was never cleared, probably. If it came on after a cycle or two of driving, then you may have a mis-routed hose or a bad part still in the mix.
Thanks!!! This was the cause of my p0401 CEL!! I took a shortcut and unbolted the whole throttle body assembly all at once and cleaned the back of the throttle body and cleaned the mess out of that hole and the rest of the holes with a wired brush, metal clothes hanger, carb cleaner, and a towel. It took me all of 3 hours with precision cleaning..
I've got a dreaded 0401 I'm trying to clear up. I tested the modulator and it seems fine, and when I blow or suck on the vacuum lines going into and out of the EGR itself the diaphram moves and the passages are clear. However, the one hose that goes from the EGR valve into the intake plenum is clogged--I can neither suck nor blow air through it. I'm testing this with the engine and key off, is that the correct way, or does the VSV need power to open and close properly?
Many thanks!
Many thanks!
Is there a way to remove the intake plenum for cleaning and vsv replacement without moving the throttle body? That way I won't have to mess withe the throttle cables, etc. if the plenum is where all the issues are why remove all the cables connected to the throttle body. Is this possible?
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #111
No, its not possible to remove the intake plenum without removing the throttle body. It is actually probably the easiest part, I recommend taking pictures of all angles before removing, however, to make sure you get your plumbing back together correctly. The throttle cables were not a challenge, as I remember.
On each cable, mark just behind the nut you will loosen with a sharpy and then loosen them up. I would recommend only loosening one side (two nuts, do just the right or left nuts) and I would recommend doing them all the same (all left or all right). That way it is easy to remember which ones you moved.
Once you are ready to install, tighten the loosened nut just until you see that sharpy mark is no longer covered by the nut. You should be very close to where the cables were when you started.
This is how I did mine and I didn't have any troubles afterwards.
Once you are ready to install, tighten the loosened nut just until you see that sharpy mark is no longer covered by the nut. You should be very close to where the cables were when you started.
This is how I did mine and I didn't have any troubles afterwards.
Damn you Onur.
You shipped too fast.
Now I have some work to do. I was hoping to put this off.
You shipped too fast.
Now I have some work to do. I was hoping to put this off.
High idle after pulling throttle body and intake
Just completed this job. My port was clear but I had to pull it anyway to get a good look, clean, and replace the VSV. My issue is that now when i start the truck (97) it Idles between 3k-2800. Ive tried hitting the gas to ease it down but I can't get it to idle lower than 2800. I let it run for a while hoping the computer would reset but that has not happened. any suggestions?
Just completed this job. My port was clear but I had to pull it anyway to get a good look, clean, and replace the VSV. My issue is that now when i start the truck (97) it Idles between 3k-2800. Ive tried hitting the gas to ease it down but I can't get it to idle lower than 2800. I let it run for a while hoping the computer would reset but that has not happened. any suggestions?
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #115
Two suggestions, 1) back off the tension on your accellerator, cruise and throttle cables going to the throttle body, and try pulling up on your accelerator cable. You may have tensioned them too much and they are pulling the throttle open. 2) Drive it. When you unplug the battery, the ECU loses its profile for how the engine was being managed for current engine conditions, it must relearn this by being driven.
I believe that your throttle cables are probably too tight, however.
I believe that your throttle cables are probably too tight, however.
You were correct. I had marked them with a sharpie but with all the oil, etc on my hands it was hard to see after putting them on. Idle is back to normal. Still kicking myself for not doing injectors though. I'll update if code returns after some highway miles (that's usually when it kicks on after being cleared).
So now I am getting a p0402 code when I start the engine when it's been sitting long enough for the engine to get cold. I replaced vac lines and labeled everything. The egr and modulator have been replaced 3 years ago. Suggestions?
Getting the PO402 after "fixing" the PO401 is not uncommon. I suffer the same fate. There are some threads, but what we all crave is to understand the problem first, then fix the issue.
I too would love to understand the PO401 to PO402 puzzle.
I too would love to understand the PO401 to PO402 puzzle.
Anyone? P0401 fixed now p0402 when starting cold only?
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #120
Here you go from the FSM:
P0402 Code
Code trips under following conditions
-EGR gas temp sensor value is high during EGR cut-off when the engine is cold - Race engine at about 4,000 rpm without load so that the vacuum is applied to port E
-EGR Valve is always Open
Possible causes
-EGR valve stuck open
-EGR VSV open Malfunction
-Open in VSV circuit for EGR
-Short in EGR gase temp sensor circuit
-ECM
P0402 Code
Code trips under following conditions
-EGR gas temp sensor value is high during EGR cut-off when the engine is cold - Race engine at about 4,000 rpm without load so that the vacuum is applied to port E
-EGR Valve is always Open
Possible causes
-EGR valve stuck open
-EGR VSV open Malfunction
-Open in VSV circuit for EGR
-Short in EGR gase temp sensor circuit
-ECM
