Step By Step Instructions For Iacv(idle Air Control Valve)/isc/throttl

[payyourtoll]

^ I finally read online that these gaskets can enlarge due to vaccum / pressure / temp and cannot be re-used.

Purchasing a new one from Toyota dealer tomorrow for $7 and can finish up

For me, screwdrivers did not work, needle nose vice grips worked on a few, but BY FAR the best method (as someone mentioned) is an impact screwdriver. They came off easily using one

thansk to OP for the write-up

[code58]

^ I finally read online that these gaskets can enlarge due to vaccum / pressure / temp and cannot be re-used.

Purchasing a new one from Toyota dealer tomorrow for $7 and can finish up

For me, screwdrivers did not work, needle nose vice grips worked on a few, but BY FAR the best method (as someone mentioned) is an impact screwdriver. They came off easily using one

thansk to OP for the write-up

One question- Did you try and clean the gasket with any kind of cleaner or solvent? Did you EXPOSE it to ANY KIND of solvent, gasoline, laquer thinner, or anything but open air??? That is the ONLY thing I can imagine that would cause it to swell. As I stated when I 1st cleaned (it worked fine after that) and then decided to replace it because of a medical emergency and the car would be 1200 mi away for over 6 mo., both times that I had the IACV off, with 7 1/2 year and 97k mi on the original gasket, it looked like new and fit perfectly both times. I can't imagine, having worked in automotive all my life, that simply being exposed to air or warm temps would have any affect on the gasket. The car now has over 140k mi and over 11 years on it and that original gasket is still holding perfectly.

I TOTALLY agree with the impact driver approach (hammered type). Needle nose vice grips are the second choice if one does not have the impact driver.

[98 ES 222K]

Thanks again to GoldenStateSilverSport. I am sure your procedure saved me at least $650 considering what dealers here in southern California charge for shop time.

For the benefit of other LOC members who may do this job in the future, I want to share a trick I learned about removing the VERY tight screws (phillips head).

I had tremendous difficulty removing these phillips-head screws (they are all the same size) => the 2 screws holding the coil on the IACV, the 3 screws holding the right throttle body and the 4 screws holding the IACV to the right throttle body. I tried tight-fitting screwdrivers, various phillips tips in a ratchet drive, vise-grips on screwdrivers, etc…but the screws wouldn’t budge. All I was accomplishing was damage to the screw heads.

I was about to give up when I thought of a damaged bolt remover tool (that uses a socket principle) I had seen advertised. My reasoning was that if I could find the correct size remover socket, that the tapered, spiral-flute sockets would fit over and grab the shoulder of the phillips-head screws. Then, I could apply enough torque to loosen them.

I found what I was looking for at Sears. I bought their part number 9-52161 (Craftsman “Bolt-Out”-Damaged Bolt/Nut Remover Set). I also looked at Sears part number 9-52154 (Craftsman “Screw-Out”-Damaged Screw Remover Set) but decided they would do more damage to the phillips heads. Bottom Line…9-52161 did a very nice job. The #4 remover out of this set engaged the shoulder of these particular screw heads well. Note: to drive the remover…I put the hex end of it in an appropriate size socket and used a ratchet wrench to drive the socket.

For those that have not seen them - these remover sockets have tapered spiral flutes inside them, which grab a damaged bolt head when they are turned counter clockwise and release the head when they are turned clockwise.

An afterthought - I was surprised to see these rather large screws in a phillips-head format. Seemed a really poor choice. I have never seen that in an American car…they use hex head instead. Yet, I don’t think this was a mistake because the Japanese designers are smart folks. Therefore, I wonder if the use of phillips-head screws in this application was intentional…to make it that much harder for non-dealer mechanics to work on? The use of these screws make a fairly easy disassembly and cleaning job WAY tougher. It would cause a lot of people to say, "I'll take it to the dealer".

By the way - I did take off the black metal piece mounted on top on the two throttle inlet holes that TunedRX300 asked GoldenStateSilverSport about. It improved access and visibility, which really helped when aligning and bolting up the right throttle body to the left one. I think it made the job easier, overall.

Best wishes to everyone. :D

Hello and I'm new to this but saw the post and wanted to know would these be okay even if the screw isn't stripped yet? I just want to save time and go straight in and finish asap, I appreciate such a great post as well, thanks.

[josephmama]

Last night I cleaned the IACV and throttle body on my 2002 Avalon XLS using this method. Took my time with the screws, gaskets all appeared in good order, everything went back together perfectly. All screws, hoses, and connectors were tightened. All wires properly plugged back in.

Today, I notice that if I'm driving down the road at a constant speed(using gas to maintain speed), when I let off the gas the RPMs will dip about 1k and immediately rise back up to the "proper" amount while coasting. If I turned off O/D, the problem is less noticeable.

Of course, my first and worst fear is a tranny problem. The second, more rational thought, is that one of the sensors was damaged or dirtied while doing the IACV cleaning.

Any ideas what the problem might be?

[ashley power]

Ok I am stressing out here. I was thrilled when I read this post last year. I did the cleaning and "Voila" worked great! I am in Florida and the July heat has come around again and my Rx is worse than ever. I am not a car girl, (but I do look pretty cute in one) my husband cleaned this last nite for about 90 minutes and once complete it was better, I drove to work today and same problems, I will list.. if anything that we may have missed rings a bell please let me know:

CEL is on and TRAC OFF light is on

1. Car shakes when idling

2. Shaking is really bad when a/c is on, almost non-existent when off, but WAY too hot to drive w/o it here.

3. When at a red light and try to acclerate, WILL NOT get up and go, takes about 60 seconds for the car to move at all.

4. Once car starts to move, will not get up to more than 25 mph for around 4-5 minutes. And then "Boom" big burst of acceleration.

And as I said as soon as I turn off a/c 95% of this goes away???

Is it possible that this was not done properly? He cleaned it all picture by picture, and said that everything is opening properly with no stickiness?

Just dont want to pay the $95 hourly rate at Lexus to get this fixed.

Thanks!!

Update!! I noticed while in park my rpms are perfect @700 and when in park the shaking is slowed down, if I rev it up in nuetral it helps, and when I turn o/d button on it is a little better with acceleration, but I was told it is bad to drive with o/d on at all times.

:)

[kan]

Just cleaned my IAC valve, my RX is running again. It helps to loosen the screws with vise grip first. I did not install the valve correctly the first time. The car will RPM will go up and down.

I took valve out and reinstall it correctly and making sure both valves opens at the same time.

Thank you very much to all !!!

[Lexbri]

I finally did this. I could not get the iacv off because the screws were too tight and i stripped one out. but i did mangaet to get the little motor off. I cleaned with carb cleaner and sopped up the stuff as it came out the bottom hose tube. I put it all back together and it purred better than ever before. Thank you all who post great info on this forum.

[DataDave]

Thanks for the instructions,

My 99 wouldn't idle at all. (Good thing that the wife can drive anything, she drove it all day like that)

I took it apart today. The screws for the throttle body are #3 philips, the rest are #2.

The head of one of the throttle body screws went round on me, so i took the whole throttle out, back to the intake

manifold. There are three 12mm nuts that hold it to the manifold. there is also a 12mm bolt that supports it from below and behind. A wrench was needed for it, rather than the socket.

Those wire holding wraps you mentioned are mounted on plastic inserts that can be pushed out of their holes, without cutting, and replaced later.

I cleaned the air valve so it moved easily, then reassembled the whole thing.

Now it idles at 2k. I don't know why it is so high.

Is it possible that the air valve needs to be in a specific position when the electrical driver is replaced?

My check engine light is on, for some reason, is it possible that the car keeps its idle high if there is another problem?

BTW I don't think there is an idle adjustment screw, and using the cable as an idle adjustment is kind of a kludge.

[DataDave]

Thanks for the instructions,

My 99 wouldn't idle at all. (Good thing that the wife can drive anything, she drove it all day like that)

I took it apart today. The screws for the throttle body are #3 philips, the rest are #2.

The head of one of the throttle body screws went round on me, so i took the whole throttle out, back to the intake

manifold. There are three 12mm nuts that hold it to the manifold. there is also a 12mm bolt that supports it from below and behind. A wrench was needed for it, rather than the socket.

Those wire holding wraps you mentioned are mounted on plastic inserts that can be pushed out of their holes, without cutting, and replaced later.

I cleaned the air valve so it moved easily, then reassembled the whole thing.

Now it idles at 2k. I don't know why it is so high.

Is it possible that the air valve needs to be in a specific position when the electrical driver is replaced?

My check engine light is on, for some reason, is it possible that the car keeps its idle high if there is another problem?

BTW I don't think there is an idle adjustment screw, and using the cable as an idle adjustment is kind of a kludge.

[code58]

Thanks for the instructions,

My 99 wouldn't idle at all. (Good thing that the wife can drive anything, she drove it all day like that)

I took it apart today. The screws for the throttle body are #3 philips, the rest are #2.

The head of one of the throttle body screws went round on me, so i took the whole throttle out, back to the intake

manifold. There are three 12mm nuts that hold it to the manifold. there is also a 12mm bolt that supports it from below and behind. A wrench was needed for it, rather than the socket.

Those wire holding wraps you mentioned are mounted on plastic inserts that can be pushed out of their holes, without cutting, and replaced later.

I cleaned the air valve so it moved easily, then reassembled the whole thing.

Now it idles at 2k. I don't know why it is so high.

Is it possible that the air valve needs to be in a specific position when the electrical driver is replaced?

My check engine light is on, for some reason, is it possible that the car keeps its idle high if there is another problem?

BTW I don't think there is an idle adjustment screw, and using the cable as an idle adjustment is kind of a kludge.

If it didn't idle at all before (hard to drive it that way isn't it?), and now it's at 2k, I'd go back and take things apart and recheck 'em, I think something isn't right. There is some adjustment on the 2 screws that hold the black case that holds the electro-magnet, but there isn't any way that could do that. You might loosen those screws and adjust it back and forth, but I don't think that's your problem. Retrace your steps.

[rx300girly]

I know this thread has been going on for a while but I have a question. In the instructions GSSS posted, there is a black plastic piece connected to the IACV. It's the part that opens to expose the pencil sized piece with the wavy washer. It's an electrical component I think. The guy at the auto parts store said this often is the problem with the IACV rather than cleaning out the steel components of the IACV. I guess this piece is sold WITH the IACV, so technically this is part of the IACV. What is this piece called? Anyone know anything about this piece? How would you test it to make sure it is working properly? Thanks any suggestions would be great!

[Dennis McGinn]

I seen no one has thanked you for a long time but I read the instructions, went out and got a can of MAF Spray and pulled out the ICV and the MAF sensor. It all went perfectly. Thank you.

Dennis

[Cathy's Rx300]

The wife's Rx300 was stuck at a high idle during the morning commute, the same after work and then a no start in our driveway that evening.

After diving in the controller was gunked up. Cleaned and it's running like a champ again

Thanks Golden!

[rxINDY300]

I have not been so fortunate yet. Like you Golden, Someone turned my screw into something that does not even remotely look like a screw. More like gold platted bubble gum that was stuck on to the part. I went ahead and just spray some throttle body cleaner down the orafice and put everything back together. It was stubborn trying to start it the first time but the second time it fired right up without any smoke. It is firing right up but it is now idling below 750 after warming up. I think that it is what it is supposed to idle at. Mass air sensor perhaps?

[TigerTee]

Super shout out to you my friend. Great instructions! Gave me the confidence to do it myself and I would guess I saved $300-$400. Thanks for taking the time to put this together. Hope you have a great 2011.

Terry in Memphis

[dchan865]

Hi, just want to provide some feedback on this great tip(s) posted by many especially GSSS and Geoff.

During the last 4 weeks, my RX300 did not idle properly during cold start. I had to step on the gas to keep the engine running. After the car warmed up, car idled fine.

I followed Geoff's short cut but ran into the problem taking off the 2nd screw on the black electric coil. To avoid further damage to it, I bought the Craftsmen bolt/screw remover(part 9-52168) from Sears and removed it. After cleaning it throughly as described. My car is idling fine at 700RPM and is running like a champ for the whole week. You wouldn't think the car has 161K miles on it. If I have issue again, I may avoid the short cut.

Thanks for the input everyone!

Cheers!

[DariusLXS]

I stumbled into this thread when I was searching online:

Tools Needed:

1) Tightly fitting Philips Screw Driver

2) Carb cleaner that is O2 sensor safe (I've seen CRC. I used Valvoline Carb Cleaner)

3) Locking Grip Pliers (definitely helped me remove the factory tight screws)

4) Small brush for cleaning

5) Towels for cleaning

6) Pliers (help removed brackets holding the hoses)

7) Latex gloves helps with limit the messiness.

* I used the same gasket and did not replace it. No problems found.

This is most useful, with your permission I would like to jot the materials / tools needed. This will be most useful to me. Thanks.

Also, thank you for this additional info. I would like to take note.

- The small washer around the pencil size metal stud.Is it wavy? This one was , or is now...

- The idle RPM , what it should be ? At P & D positions.Engine warm. As the owner tried to raise the RPMs by tightening the throttle cable. It did help , but now it was idling way too high.And where is the idle screw ? If there is one...

- How much cleaning is required ? I cleaned allmost everything I could. The rotating piece (?) that comes off , and has these moving flaps , etc etc how much can you clean ? How much MUST you clean ? I managed to use the carbspray as a solvent , so most off the sh.. did come out.Some still remains. Should I worry ?What is the purpose of this "valve" thing? Does it suffer , from this "solvent cleaning abuse" ? It was stuck , when I opened it.Now it moves really freely.

A warning , the screws ARE TIGHT !!! Do not attempt with the wrong size screwdrivers !!!

The instructions are clear , and even I managed to do it ! And the result was impressive.... atleast I am happy myself !!!

I would like to relay this to a friend's twitter.

Plus, the step by step instructions are very well crafted. This is a great find.

1) Remove the hose that comes from the engine/motor that connects to the air intake hoses.( Hose is below in red – we’ll refer to this as Hose A) When you pull back the rubber hose covering, you will see that a metal bracket is holding the hose pretty tightly in place. Use the pliers to clasps the two metal pieces together to loosen the bracket and pull the hose loose. You can also do this by hand if it’s easier for you.

Attached Image: original_2.JPG

2) Upon removing the hose, you will want to remove the two air intake hoses. Loosen the three screws above in green and remove the hose. Below is a picture of the intake hoses removed.

Attached Image: intake_hoses_only.JPG

3)After removing the intake hoses, I opened the lid to the air filter and moved this to the side of the car to create more working room. I believe there are two clips on the right holding the lid in place. Just pop the two clips and move the cover to the side. I also took out the air filter and temporarily moved this to the side.

Attached Image: intake_hoses_removed.JPG

4)After removing the intake hose, the throttle body/IACV/black electric coil is revealed. At this point, I removed the black electric wire from the black coil. Once the electric wire is removed you can remove the black coil from the IACV by removing the two screws. Note, the screws are factory tight so use a tight fitting screw driver to remove the screws. One of my screws was partially stripped from the dealership’s work, so I had to resort to my locking grip pliers which helped out tremendously. After removing the two screws, the black electric piece pops right off. When the black electrical coil is removed from the IACV, it exposes a small pencil sized metal stud. You will also notice a washer that sits on this stud. Don’t lose this washer. Take it and put it aside so it doesn’t fall off when you continue on in the next steps.

Attached Image: throttle_body_revealed2.JPG

5)Additionally, I removed the hose coming out of the IACV. We’ll call this Hose B. This hose can be removed in the same manner by clamping the bracket and pulling the hose out. You will see that the hose is removed below. Below are pictures of before and after.

Attached Image: sensor_removed2.JPG

6)Here is where the fun begins. I initially attempted to remove the four screws attached to the IACV at this point, but found that after an hour, this would be nearly impossible to remove considering the location of the screws were in an extremely tight spot. The only way I would be able to remove the IACV is to remove right throttle body. Not as tough as it sounds. Three screws need to be removed to accomplish this. Again, be careful when removing the screws. Also you will see I removed another electric plug and I also cut a tie wrap. Once you complete these steps, the throttle body/ IACV comes out pretty easily. Note when you remove the throttle body, there will be one LAST hose connected to the IACV. Be careful when you remove this hose as radiator fluid may spill. Some of my fluid spilled out so I just refilled my coolant after I was done.

Attached Image: throttle_body_connected2.JPG

7)Below is a picture of the bottom view of the IACV. You now can EASILY remove the four screws connecting the IACV to the throttle body . In the picture below, I have already removed one of the screws.

Attached Image: bottom_view_iacv.JPG

Once the four screws are removed the IACV and throttle body separate. Now you can clean both of them with your carb cleaner, brush, towels, cotton swabs etc…. Picture here is before I the cleaning with all the muck inside

Attached Image: iacv_removed.JPG

Pictures after I cleaned the IACV and throttle body

This last picture is the post throttle body cleaning

Attached Image: post_throttle_body_cleaning.JPG

Attached Image: iacv_upclose.JPG

Attached Image: iacv_post_cleaning.JPG

8) Once you are done cleaning, just put back the throttle body/iacv the same way you took it off, and put everything back in reverse order. Ensure the gasket is in place. Also, ensure you put the washer back on the electric coil. Make sure you place hose A & B back and ensure the electric plugs are back in their original position. Once these things are in place, then it's all about putting the air filter/hoses back and you are good to go. If you have lost any coolant, make sure you refill it to a safe level.

After completing this cleaning, my car starts up without any problem and idles as if I just purchased the car brand new. Replacing this at a dealership would have costed me $300-400 easily. Let me know if you have any questions. Cheers (Also, I tried to post these as separate replys, but the software combined all my replies into a single reply and did not keep them separated)

I would like to thank everyone again.

[Storm52]

Thank you for this thread. My 2002 Avalon was exhibiting the same issues, dying immediately after cranking and having to hold the accelerator down until the engine warmed.

The entire process took me 1 1/2 hours from popping the hood to go-jo on hands. I took the cover off from the 2 throttle bodies as suggested. It was easier to replace the right TB after cleaning. The most difficult issue actually was removing the hoses from the TBs. The old screw issue I had was with the TB cover. I disconnected the 2 electrical connections (one on the IACV and other on the TB) and then removed the right throttle body. I then removed the coolant hoses as it was easier with the body removed to access the clamps. The IACV magnetic cover was removed, found the 'wrinkle' washer. Removed the 4 screws that held the valve to the TB. I was able to save the quick tie that held the electrical cables by inserting a flat blade driver in the slot and pulling the strap out.

I cleaned the entire TB and valve and had the idea to use my dremel with some flitz polish to smooth out the casting marks on the valve where it feeds into the TB. Wasn't necessary, but I was into removing all gunk. I thought about removing the left throttle body to clean it, but after seeing the cabling and throttle controls I had a moment of clarity. I did clean out around the butterfly valve and intake. It went back together in reverse order and fired up. Idle had been running about 1100rpm never settling down below 1000rpm. After the cleaning it ran around 1200rpm and I took it around the block. After cranking about 4 more times, it has settled to about 800rpm in park and approximately 750 in drive.

Thanks to everyone that contributed and added their tips.

[ml30306]

I just did this procedure on my 2000 Lexus ES300. It is just slightly different since I had to remove one more hose on top of the box that connects to the 3 air intake hoses. I did not have an idling problem, I just notice that when I cold start the engine the RPM's are at around 1700 before they go down, which I assume is normal from what I read? I did want to check though if there was any dirt inside the IACV, there sure was. I used some clean rags and rubbing alcohol, making sure I cleaned off any moisture and I let the items sit for a while for the alcohol to evaporate. I will call this "preventative maintenance" in my case.

The directions are very precise, clear, and easy to follow. Thanks again for posting them, wish there was more procedures like yours on this site!!!

[ml30306]

One more thing to be added: The 3 screws are really horrible to remove. I was lucky on 2, the last one would only turn using a regular small vise-grip wrench. Glad it worked since the head was almost completely stripped.

---->>>> It is well worth the time and money to replace those screws with hex bolts. I got 3 at ACE, 3 bolts size M6 - 1.00 pitch plus 3 washers. TOTAL COST = $3.52. They work well.

[Hadyourphil]

Do these instructions exist anywhere with the pictures attached? My '01 RX300 just started having start-up problems (low idle speed, especially) and, at 178,000 miles, I probably should clean the IACV.

[ml30306]

Login to your account, go to page 1 of this thread and the instructions are on that page with pictures.

[Hadyourphil]

I did discover that right after I posted. Great instructions!!!

Some observations after doing this yesterday:

A #3 Phillips and a firm grip loosened the throttle body screws just fine. The "wavy washer" fell out and was not discovered until the car had been reassembled. I do notice the idle is now double the 700 rpm listed as normal. And, I also have noticed that others have had higher idle after doing this procedure but no one seems to have offered a solution!

The wavy washer is brass, so if it falls somewhere, a magnet will not retrieve it. And, if I decide to reinstall it, where exactly does it go? Over the magnetized piece on the end of the sensor? BTW, that's why the washer is brass... so the magnetism will not affect it. And, I did something you really should not do but has seemed to work. The oddly-shaped gasket that goes between the ISC valve and the throttle body expanded and would not fit back in its groove, so I carefully cut small pieces out of the longer ends (three cuts, IIRC) and managed to get a tight fit when everything was bolted back together. I'm not too happy with this, but so far, so good. Notice that the new gasket is less than $5, so I may get one just in case.

So, any further thoughts on the elevated idle speed??

[Hadyourphil]

Well... guess no one had any thoughts!

I've noticed my idle speed settled down after a couple of days. Now, on initial startup, the idle is around 1200 rpm. It settles down to 700 after a few minutes. OK for me.

[gau]

Thanks for the write up... did my today... idle issue gone....

I don't if this help: but if u remove the air filter box that will give u plenty of room to use the impact screwdriver (purchase for $5-$7 @ harbor freight) and a hammer. I didn't strip any of the screw.....