The complete Solution for EGR system in RAV4 4-Door 4WD(3S-FE) - Toyota RAV4 Forums
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post #1 of 19 (permalink) Old 11-10-2011, 12:39 PM Thread Starter
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Post The complete Solution for EGR system in RAV4 4-Door 4WD(3S-FE)

Hey guys, since I am indebted to the online resources especially our RAV4world, I am writing for the complete solution for the EGR in your RAV4- 4 Cylinders SUV/4 doors/5S/Automatic:
Tools:
· A helper, a rag, vacuum pump and a vacuum gauge, few metric wrenches and ohmmeter.
EGR (Exhaust Gas Recirculation) system consists of:

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Function of EGR system:
EGR returns some of the exhaust into the intake manifold and it is necessary to lower your engine temperature so your engine can operate on high speeds without being too hot, reducing environmentally harmful emissions, and it saves gas too.

· High EGR flow is necessary during cruising g and mid-range acceleration, when combustion temperatures are very high.
· Low EGR flow is necessary during low speed and light engine conditions.
· NO EGR flow (Engine Warm Up, idle, wide open throttle)

From Q to the EGR valve, Vacuum (open valve)/Air (close valve)

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Theory of operation (simplified):
at low RPM=low temperatures
VSV has a lot of feedbacks including engine Temp. will apply air through Q to close the EGR valve.
Exhaust will flow to the modulator and released to the atmosphere through the modulator filter.
at High RPM=high temperatures
When EGR is needed, the VSV will apply vacuum coming from the modulator to open the EGR valve to allow some exhaust to flow.

1)Modulator:Check the vacuum Modulator (The cap always has P, Q, R letters on it)

· Clean the filter using compressed air.

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Disconnect the hoses form the modulator and label them. Block P and R and blow Air into Q.


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Air should flow to P and R and should feel it.

Run the engine and with a helper keep the RPM at 2500.


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Blow air into Q, air shouldn’t pass through (that means that the EGR system is working and it applies some vacuum on Q to open the EGR a little bit)
>>if either of these functions doesn’t work, replace the modulator.
EGR valve operation with VSV:
Using a 3-way connector, connect a vacuum gauge betn. EGR valve and VSV.
Start the engine and check that the engine starts and run at idle.
Using SST connect terminals TE1 and E1 of the DLC(diagnosis labeled box in the engine compartment)
>>Engine is Idle, cold and at 2500 r.p.m, Gauge should show 0 vacuum.
>>Engine is idle, hot and at 2500 r.p.m, gauge should show some low vacuum reading.
(If not so the VSV –EGR valve operation is not working).

2)EGR valve
While the engine running and cold, apply 10” of vacuum to the Q port on the EGR valve using a vacuum pump, if the engine stalls it means that the valve is ok(it stalls due to the exhaust flow to the air intake, which the engine doesn’t need at that moment).
If not ok, replace the valve (easy)

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3)Vacuum switch valve (VSV)
Always make this the last one to check.


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With an ohmmeter check there is continuity between the two terminals.
Resistance: At 20 °C (68 °F): 33 - 39 ohms
If there is no continuity, replace the VSV

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Check that there is no continuity between each terminal and the body.
If there is continuity, replace the VSV.

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Apply battery positive voltage across the terminals.
Check that air flows from port E to the filter. If operation is not as specified, replace the VSV.

From my experience, the VSV will be the faulty one, the valve and the modulator have longer service life.
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post #2 of 19 (permalink) Old 11-10-2011, 07:46 PM
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Thank you very much! This will help so many of us,very well done.
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post #3 of 19 (permalink) Old 11-10-2011, 08:53 PM
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The VSV looks the same as the ones that control the hubs on a suzuki.
When it is off, the pipe marked E should be blocked off, and air should flow from the filter to the unlabelled pipe.
They usually fail leaky from port E to the filter. A squirt of Magic Spray down port E and a few on-off cycles usually sorts them out.
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post #4 of 19 (permalink) Old 11-13-2011, 08:26 AM
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the egr issue on 99.9% of this gen of ravs is the vsv. located on the back of the engine and can be seen and switched out from the passenger wheel. cost is $50

there will be some pain involved with this fix. there isnt a lot of room. im 280 lbs with half way fat arms and i about came to tears from having to jab my arm in so far. but i fixed the issue in five minutes vs a minimum two hour fix for the normal person.

you turn your wheels counter clockwise as much as possible and lock the steering (take out key). get a flashlight and locate the switch. once you have the new one to judge from, it is easy to find. reach your arm in there as far as you can and undo the wire connector. pay particular attention to which color vacuum hose goes to which one.

wrap your hand around each vacuum line and push against the vsv with your thumb until it comes off. if you can do a little twisting with the lack of room you have to 'break the seal' then do it. otherwise pulling it off will require decent hand strength. yes you run a chance of causing a leak but my 11 year old rav lived through it just fine.

then plug back in the new switch and let it hang. use the electrical wires to wrap around something to take out the slack. i am three months into the fix and my egr issue hasnt come back.

this fix is my first post on here and with the above title, i hope it finds a couple people and saves them a ton of time in research on here and in playing the 'grease monkey' role. be well and thank you all for your knowledge.
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post #5 of 19 (permalink) Old 11-26-2011, 06:02 PM Thread Starter
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Needa, u r totally correct VSV is the main thing. Everybody was saying that and I didn't believe it until I diagnosed it myself. The mechanic was chasing his tail about which component caused the fault:the regulator, the valve, or the VSV. I spent $100 for a new modulator based on his own guess and the second time he guessed again, so I decided to take it on my own. it costed me $60 to fix myself plus some time and help from my in-law, I saved about $600.
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post #6 of 19 (permalink) Old 11-27-2011, 12:02 PM
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yah i, like most everyone else, start buying and/or start messing with the things that you can see from the top of the engine. i personally unhooked and cleaned out my egr valve three times before i replaced it. each time i cleaned it... my car ran great for a couple trips to the store. i knew it was as clean as it was going to get....but i figured it was sticking somehow so i spent 150 plus on a new one

then i came on here and read around. finally found info on the vsv. it took me months to get around to replacing it... but im so glad i did. just wish i could figure out this other thing i have going on.
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post #7 of 19 (permalink) Old 12-17-2011, 04:24 AM
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EGR System in Rav4

Perhaps, some of you could help with my EGR problem in a 1996 Rav4 with 175,000 miles.

The EGR valve has been having both codes for stuck open and stuck closed.

An EGR modulator was installed Dec. 2010 when my front converter was replaced. The converter "blew" is how they described it and pressure had built up in the modulator causing it to "blow" too.

The check engine light first came on in the summer while I was traveling.

A shop checked the codes, I told them about the work in Dec. they checked the system, reset, drove, light came back on and reset again. They explained the system a little and said it is safe to drive.

It seemed to run fine so I didn't worry about it the last few months.

I needed a battery a few weeks ago. That shop checked everything over, cleared the codes, drove it etc. When the light came back on they told me the same thing. It's safe to drive.

I decided to return to the shop that did the work in Dec. 2010 as I had noticed in the recent cold that it sometimes seems to lose power as I am driving and stutters a little bit. When it does that, it feels like the gas pedal is harder to push in or resisting.

They have had it in the shop twice.
The first time they replaced the VSV. I spent $ 330 for parts and labor for them to replace the VSV.
The next day, the light was back on.
2nd time they cleaned, checked connections and hoses and put air through the system. They started and drove it several times.
Tonight, after picking it up I made 3 stops. On the way home after that, the light came back on.

I will be taking it back to them on Monday.

I printed your post and diagrams to take with me.

Any other information any of you could share would be greatly appreciated.

Thank you!!!
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post #8 of 19 (permalink) Old 01-16-2012, 12:05 AM Thread Starter
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Can you put the codes here? is it P0401? if so?
and Since you changed the VSV and the modulator, can you check the EGR valve(refer to the main post i think u can do it urself)?
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post #9 of 19 (permalink) Old 02-22-2012, 02:27 AM
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I had the EGR code a few years ago and, yep, the problem was the VSV. I offer my experience for someone who tackles this for the first time.

My original VSV is safely in its place!! It's not connected to anything but it's still there.

For those with 4wd who tackle this, you might find it impossible to get the old VSV (I tried for hours, yes, took the wheel off, blah, blah, blah) and just couldn't get to it. I managed to get the vacuum lines and electric connector off, then DOH!!, there's nothing magical about where they originally mounted it (just about the worst location possible). I found an unused bolt hole on the back of the motor at a much more convenient location, mounted the new one there (need the right size metric bolt), and hooked it all up.

2000 RAV4 AWD 5-speed
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post #10 of 19 (permalink) Old 02-22-2012, 08:47 AM Thread Starter
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Well done...I think it might me easier with the V6 and the newer models since they are bigger..
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