Code P0401 on my new cruiser

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Darwood

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Ok, I just got my scan tool today and found out that I do have the dreaded code P0401. I don't have the FSM so I'm not sure what the procedures are to determine what is broken, but I decided to poke around anyway.

I took the advice I had seen on this board and checked the EGR vacuum modulator (that's what my great Chiltons calls it). Now I'm not really sure this is what people were talking about when they were talking about a filter. Is there also a filter in the EGR valve?

Anyway I took pictures of the modulator and filter that was in it. Apparently the detailer at the dealer that I bought the truck had no qualms about using 100 gallons of water to clean the engine.

So here are the pictures... what do you all think... sorry about the quality, I'm still trying to figure out how to use the macro on my camera. As far as I could tell it looks like someone tried to use the filter for their charcoal fish-tank, or tried to use it to strain coffee grounds.
::)


egrmodulator1.jpg


egrmodulator2.jpg


egrmodulator3.jpg
 
Scamper

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Have they updated that part? I have a '97 and my filter was white (well, almost white) and had only a small dark spot on it. That filter looks totally black! :doh:

And what's that suff on top of the unit in the last picture? Looks like someone used it for a hibachi. Is that rotted black filter element?

Tom

Edit: to clean you just blow compressed air through the filter pad from the back side, but that filter looks pretty bad if it's supposed to be white.
 
Beowulf

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Derek,
That is the EGR modulator; the OEM filter on my 97 was also white.

>> Is there also a filter in the EGR valve? <<

No.

>> I forgot to add, how the heck do I clean this? <<

Good question. Tom described what the FSM recommends for the filter. If that black filter is coming apart then you should buy a new EGR modulator. If that black filter is from carbon then I'm not sure what to try but I guess cleaning in carb cleaner would be the first thing. If those are carbon particles where the filter sits then clean them as best you can using compressed air and carb cleaner. I soaked my EGR modulator in carb cleaner and there was a little carbon cleaned out of the ports but that didn't fix my P0401. Neither did a new EGR modulator.

Be sure to test the EGR modulator with the procedure posted by Rick.

-B-
 
Darwood

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Thanks Rick for the procedures. Yeah I'm pretty sure the filter was white at one point. It's just caked with carbon now. The stuff on the bottom of the modulator I'm pretty sure is carbon. I think if I put it back in the truck for a while I'll soon have diamonds. :D
 
Darwood

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I just got me a new modulator... we'll see if that makes the light stay away. I figured it couldn't hurt since the old modulator was toast. ::)

I need the light to go away so I can register this thing in Cali. :mad:
 
Darwood

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Well it's been about 5 days, and the check engine light has stayed off. Also I don't seem to have any stored codes in the ECU. So it looks like the modulator was the immediate problem.

The next test is SMOG...
 
Darwood

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Just as I had suspected. I post the above and the check engine light comes on while driving home from work. This leads me to believe that the EGR system is also linked to this message board.

So how do you check the VSV again?
 
Darwood

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Ok so my new code is 402: Exhaust gas recirculation flow excessive detected.

I did a search on the board and could not find anything for this. After looking in my great Chiltons it appears that the problems are all the opposite of a 401: EGR value stuck open, EGR VSV open malfunction, open VSV EGR circuit, short in EGR temp circuit, and last ECM.
 
Darwood

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After more inspection I've found that I got carbon clogging up the works. What Cdan posted about the tube going through the intake plenum getting clogged applies to me. Looks like I'll either be trying to clean out the plenum or bypass it with some hose. I'm also going to guess that the VSV is toast, or shall I say carbonized. :-\
 
Gumby

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If you have a scan tool to check for the codes, you can check the monitors as well. The EGR is a tricky one. The vehicle has to be driven just right to get it to enable. It's also a two-trip DTC, so you have to drive it twice just right to get the light to come on.

The state will check monitor readyness, so you must fix the problem, you can't just erase the codes.
 
Junk
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[quote author=Gumby link=board=2;threadid=9832;start=msg90213#msg90213 date=1074085331]
The state will check monitor readyness, so you must fix the problem, you can't just erase the codes.[/quote]

Yeah, I kind of found that out.
s42.gif
 
Gumby

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Someone needs to make a program that triggers the monitor status to ready and not let the monitor read what it's supposed to be looking at.
 
Asiarider

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[quote author=Junk link=board=2;threadid=9832;start=msg90441#msg90441 date=1074114680]
... or better yet, someone right up an EGR section I can actually understand
BIGYuppyAcid.gif

[/quote]

Your Momma can explain it to you :D

Mike
 
e9999

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dang, Mike, you must have been exposed to some bad influences...
:D
E
 
Asiarider

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[quote author=e9999 link=board=2;threadid=9832;start=msg90925#msg90925 date=1074156610]
dang, Mike, you must have been exposed to some bad influences...
:D
E
[/quote]

Yes, too Junk :D

Mike
 

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