Egr valve passage cleaning
 

1999 Camry LE 4-cyl

Where to start cleaning EGR valve passages?

Remove EGR?

I forgot to note that I already removed it, and sprayed some throttle cleaner inside of it to clean out the built up dry carbon if any at all ( black stuff came out ) and let it dry overnight before putting it back in. I still get the check engine light for error: P0401

Possibly be EGR Modulator? Any other suggestions?

I don't know how much built up encrusted carbon there was but I've always had to use different scraping things to remove it, screwdriver, wire brush, etc., as well as carb cleaner and compressed air. You can buy a small dip tank from parts stores to soak overnight but keep vac valve above it. I also use a vac pump to open the valve and clean the valve seat being careful not to damaged it. There would have to be a lot of carbon to get insufficient flow. Did you test EGR by using vac pump to open it while engine is idling? If the engine stalls then you're getting flow. You'll have to check out the whole system, including the exhaust tube, VSV and modulator. Don't discount possible sensor problem.

Likely your EGR VSV. With your engine running in park- rev the engine and see if the EGR pintle moves. If it does- you just verified the EGR modulator works and all of the vacuum lines are intact. Problem is- the EGR valve SHOULDN'T move- because the EGR VSV should be blocking vacuum to the EGR valve until certain running conditions are met. The reason why the valve would move at this point is because the EGR VSV is stuck open- allowing vacuum to reach the EGR at all times. How does this cause an EGR flow insufficient code? Because the ECU monitors MAP sensor readings before and after the EGR is activated. It should notice a drop in manifold vacuum. Since the EGR is already active due to the failed VSV- its doesn't notice the drop and interprets it as a low flow.

CORRECTION- EGR will valve will move for a split second- then become inactive. It it stays on the whole time you have the engine revved- the VSV is stuck open.

JJ

yes, from what I gather on web,,,most people are pointing to the vsv switch and not egr.

I had same egr problem and just got vacuum pump and hook up to egr port with engine running. with the vacuum pump engage and pumped, Engine wanted to die and started to run rough which means that the egr was working. So then I had to get at the vsv switch which control the egr and it was located way at the back of engine block and bottom part against the engine firewall part. It took me about 1hr just to take it out, trying various ways to get it out. finally got it out and tested the vsv switch and noticed it was plugged up with carbon... yeah got a small drill bit (use it by hand, not power drill) and put it in and started to clean it out. And once it was clean, started to blow in pipe on vsv switch by mouth and can now feel the air passing through. After cleaning the vsv switch, I relocated the egr vsv switch assembly to the top right rear side of engine assembly---passenger side and cut some length of vacuum hose and rerouted for easier access for next time--should it require troubleshooting or access.

A lot of people say to buy new VSV switch but its $80 fo rnew one and I am cheap... So try cleaning it first. My car was a 96 camry 4 cylinder. maybe I will take some photos of it and upload.

good luck

thanks guy/gals for posting this info...I bought a used 1996 Camry V6 with 220k miles on body/trans and 60k miles on replaced engine. It still rides good barely any noises I have to replace the power steering pump due to leak from it but no rush this is my beater...when I cleaned of EGR of built up carbon the part that connects at bottom to pipe/tube that I think goes to exhaust got cracked thus now I have a leak causing extra engine area noise anyone know of an online store where I can buy a replacement EGR? It seems the manifold(I think its called that) is all one piece with the EGR am I guessing wrong?

go to your local import junkyard. I got mine there for $15 for whole thing, egr valve, tubing connector part. You still didn't say what code you got.

Thank you!!! It was the PO401 codeand taking EGR valve off and cleaning the carbon gunk all in it was all I needed and warning is gone now. The problem now is the area where 2 screw mount the tubing that leads to exhaust well one was broken and the only good one is now cracked due to overtightening. So now engine noise is more pronounced due to that. So now it looks like I need to get that whole piece again but don't want to overspend that all.

Hey it's been a while...well I recently had the EGR replaced with a used one from junkyard..instantly the car felt smoother...I erased the code and drove it..it was gone for a while that day but return shortly after I shutoff engine and used car next day..well I am partially disabled but I still try..I decided to go after the VSV and honestly am a little confused..I thought there was one but following hanes repair book saw 3 VSV on top of engine...anyway can someone tell me best way to clean the VSV? I presume I can soak everything except the electronics right? Also how do we know the EGR modular filter had its use? Mine look dirty even though per hanes book instruction I air blew it out. I have the V6 3.0 engine...I ohm the VSV and it showed 38(book says it has to be between 33-39ohm) to OHM it I had weird off the charts #s but changing selections on volt meter it got to 38 ohms BTW I write cause I worked on VSV on Saturday and erased code but after 20 minute ride turned off engine and after restart I noticed same code p0401....

Any reply?

I wanted to add to this for future reference about the V6...the VSV is located on top of engine under that little engine cover in front of EGR over throttle body....there are three but the one with the vacuum tubing coming from the modular into the VSV and out going to the EGR is the one the others are for other systems thus totally unrelated. After speaking with a mechanic I learned that ohm testing needs to be done by removing part and adding DC voltage like that of a car charger...turning car on doesn't give you true ohm by what I was told anyways I gathered this from that the VSV is closed and when asked mechanic told me yes so if you can blow thru it the VSV is stuck open..I cleaned it out prior to reinstall and testing and it blows thru..I am having it DC powered to test it later this morning afternoon. I have a thread where a member posted info on how to clean it..(VSV) the ohm range of a working VSV according to Haynes Manual is between 33-39ohm.

It appears my VSV is defective. I took it out and if was told one can't blow thru it..which mine does....looks like this might be my issue. There would be no point to take the VSV apart again since if not powered the VSV stays shut thus can't breath through. The ohm test is next once I get 12 volt power other then the car.

Was your VSV all plugged up with carbon deposit.. If it was and you cleaned it, then all you would have to do is plug it back in car. Don't reset the check engine lite, then take a drive and get above 60mph and then stop somewhere, turn key off and then on again, do it 5 times...It takes 5 error codes by car computer for check engine lite to come on...

but if you fixed the problem, the lit check engine lite will go while you are driving and you will know that you fixed the problem.

Most likely VSV is not faulty electically, just like the EGR, modulator.... Most emission parts problems are usually related to all carbon deposit plugging up emission parts, like egr, VSV, vac lines and others... Now I don't know about Oxygen sensor that much...

You got nothing to lose, so plug it back in and see if it works... Don't start trusting mechanic for solutions without paying $$$ for it and that's even if they fix it.

No it wasn't plugged up but OK...is it true that to check IF I can blow thru the VSV valve that if you can feel the wind on the exit that it's faulty....can someone verify this please? Also the 2 other VSVs on this V6 can I use those in place of this VSV thus leave the faulty one(if it is) in whichever I use...if it don't effect emissions? It's easy to verify on any V6 itd held with a screw on opposite side.

OK no reply to my last response yet so I'll go ahead and add this !!PLEASE CORRECT IF WRONG!! I tested the VSV for my 1996 V6 Camry first with NO POWER I attached a vacuum hose on entrance and exit...I held exit hose in a cup of water and blew air thru the entrance and air made bubbles in water...I performed same task this time holding entrance vacuum hose in water and blew thru exit vacuum hose and bubbles once again...then to make sure IF it had to be powered to force VSV to close it's valve I attached VSV to it's engine harness connector meaning it has power once I turned key to before turning on engine position...re-performed steps above in same manner a still bubbles appeared in water..so my conclusion unless proven wrong is my VSV is not working so next is to get a replacement VSV and hope that was the issue.

P.S. I USED A VOLT METER ON HARNESS VSV CONNECTOR TO BE SURE IT HAD DC VOLTAGE ONCE I TURNED KEY TO PRIOR TO TURNING ENGINE ON POSITION.

Is the VSV you refer to shown in the photo?

Does the part have two small vacuum hoses connected to it?

Does one hose go to what looks like a can on the EGR valve (the EGR having 1 vacuum hose attached). The other hose going to what also looks like a can type item that is located next to the EGR valve (this can has 2 vacuum hoses attached).

If so:

The ohm reading should be 33-39. This is with the electrical plug to the part removed.

There should be no continuity between the valve case (part that is steel) and either of the electrical terminals on part plug.

When the valve is NOT powered, air should flow between the port (tube) nearest the round barrel on one end of the valve (let's call it Port A), and the port at the other end of the valve (Port B). Thus Port A is connected to Port B.

When the valve IS powered by 12v DC. Air should flow between Port A and the round barrel (let's call it Port C). The round barrel is actually another port but it vents or is open to atmosphere. The round barrel is a screen/filter to keep debris out of the valve and hoses.

When the valve is powered, Port A is no longer connected to Port B. Port A is now connected to Port C, which is vented to the atmosphere. Air should NOT be flowing between Port A and Port B, but from Port A to Port C.

Check airflow between all the ports as stated above.

When the VSV is powered, the EGR system is off.

If the valve has 3 hoses attached to it, post back.
__________________

yes the vsv you mention is same I speak about. I ohm before but with power and plug inserted and got a 38.95. The ports A and B are the only 2 I am testing not the one with the filter thingy on it(roundish) with and without power I can breath thru port A and B thru either direction.

This is it in picture. I used a vacuum hose attached to side where plug inserts facing west I call that port A...then another vacuum hose on end facing north between roundish filter thingy and description saying "Toyota" that's port B.

When the VSV is not turned on (powered by 12V), air should flow between the west plug and north plug.

When the VSV is powered by 12V, air should not flow between these 2 plugs. Air should now be flowing between the filter and the north plug.

When connecting the VSV plugs to the vacuum hoses.

The North plug goes to the actually EGR valve.

The West plug goes to EGR modulator valve. This looks like a can mounted next to the EGR valve.

When the VSV valve is powered by 12V, the hose going to the EGR modulator valve is vented to the air by the filter. This venting disables the EGR system.

When the VSV valve is not powered by 12V, vacuum is allowed through the valve to the EGR modulator valve. This allows the EGR system to now operate.

lol..that's basically what I said. I get airflow thru both sides with bubble test powered or not. I'm only talking about the north and west facing air ports not the port with round filter on it.

One test for a plugged EGR valve is, with engine idling remove the hose going to the EGR valve and apply vacuum. This will open the EGR valve. If the EGR system is clear exhaust will be routed into the intake causing the engine to run rough or die.

What's an option that cost effective to get something to apply vacuum? rather a machine or use of personal air...i/e like applying air into a vacuum tube via my mouth?

Basically I'm trying not to have to spend, spend, spend....I tried to weed out possibilities:
1. Replaced EGR
2. Tested the VSV on and off to see if air passes thru the important ports.

At this point I'm waiting to get a used VSV from a junkyard.
My plate sticker is required by end of 10/2010

I think my friend is exhausted with trial and error already so I need to find resolution quick.

EGR P0401 error - emissions
 

So, I have read the forum on EGR system fixes on 1996 4 cyl Camry. I've removed hoses and started to clean. I had the larger hose between the EGR and modulator off during idle and it is blowing air out of the egr. Is this normal?
Mike

I used one of the short hoses going to the modulator to maniually (by mouth) create vacuum on the EGR. It works without much force.

TY I'll try today

wat does?
 

wat does putting a filter instead of a ccv do to the performance of the car?

What'a a CCV? Also any discounted tickets to HIN-Chicago this weekend?

I finally just performed this test and during applying vacuum the engine while idling started to quickly run rough pretty sure with continued vacuum the engine would have stalled all together. So basically that clears I believe the EGR so it's goes to the VSV again which I'm pondering getting new...since the junkyards are limited on the V6 Camry. I still have time.

Thanks worked great!:D

Its basicly a pcv system just runs the opposite direction valve so instead of positive crankcase vent its just crankcase vent so my train of thought is less pressure is more power


And yes on the website link there should be an add of a 5 dollar off to it using the coupon code I usually post links to discounts for the car shows on the site so just keep ur eye out and use the current coupon code on the site

Ok I replaced VSV with another same part number..tested it and when powered it won't permit air to pass anyways I reset light and it came back...I had applied vacuum to EGR and engine started running rough which by what I understand signifies the system through the EGR is clear..now let me say I bought car with engine replaced with another identical engine from Japan so EGR system had to be installed on this engine..asking the previous owner the car had no engine light for about 6 months after engine was replaced anyways I'm wondering if maybe some sensor or something was missed..here are some obdii scanner pics if anyone can figure anything that may help please advise.

Sorry here are pictures straight.

The computer does not monitor every sensor.

Was the CEL on when you purchased the car?

Sometimes Japan engine emissions systems are different then US.

Have you reviewed how the EGR system works? The link below has some info on this. Your system may or may not have an exhaust temp sensor on the EGR valve.

http://www.autoshop101.com/forms/h61.pdf

Hey buddy I have a 96 V6 and even the Haynes book doesn't exactly specify actual location unless I missed it..can you inform me where the location may be? I stumbled into something that appears to be it while looking thru repair manual is the location there really close to EGR by throttle? It is a plug or part of a plug?

BTW my cel is still P0401

I've done the following thus far...

1. replaced EGR and VSV
2. Did vacuum test on EGR(replacement) it ran rough when vacuum applied, tested VSV(replacement) and when powered it didn't permit air to travel from 2 actual ports used from vacuum hoses coming from EGR modular and other port going to EGR.
3. All hoses look and tested clean that pertain to EGR system.

When I erase codes it seems that no matter my type of driving the code comes up after I take a ride 1 or 2 different times...in most cases after car has been turned off. Now honestly the car is running flawlessly with no burning of anything i/e oil. Like I mentioned before car had engine replaced with Japan engine and like 3 months before I bought it the code appeared...he replaced engine like a year before selling it to me. I heard from a friend that his friend had a similar issue and with a replacement Japan engine in his particular case it was a sensor and as for code he had it's unknown.

See private message.

See link for a photo of the EGR temp sensor.

http://www.rockauto.com/catalog/moreinfo.php?pk=1002036

IF the engine has one it would be on the EGR plumbing. The photo below shows the boss it screws into to on the EGR manifold.

http://www.rockauto.com/catalog/moreinfo.php?pk=939878

Your car being a later model may not have one any more, I don't know.

See private message.