How to test a rotary type Idle Speed Control Valve
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- Опубликовано: 5 ноя 2016
- Idle speed control valves are responsible for providing a fast idle from cold start to ensure an engine warms up quickly. They also allow the ECU to increase engine RPM should a large load be applied by say the power steering pump, Air Conditioning compressor or even if the alternator is having to produce a high output.
In this video I cover the removal, inspection, resting and operation of a Toyota rotary type Idle Speed Control Valve. These are very common unit used on may Japanese vehicles. There are actually quite reliable as a unit but do become contaminated by dirt over time. They are also a possible source of an internal coolant system leak, often very difficult to detect too...
If you have any questions or comments then please add them below.
Andy Mechanic. 
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Thanks Andy, great YT episode this the first time watching you, I am a retired Electronic service technician, so this is the other side of the my trade profession that I am used to, my mechanical limit is 2 or 4 stroke scooters that I own one been a 1986 SH-50T Yamaha Mint and the other a 1988 CN-250 Honda Maxi scooter, once again cheers and thanks for the time and effort put into making this.
I currently enjoy repairing for family and friends electronic keyboards and radio's among other things as a interest to keep me busy but not for monetary gain.
The best explanation you can ever get on IACV operations
The best technical video I've seen! No one else can give such a 100% perfect and clean idea about the throttle body like Andy! I have benefited so much that I do not know how to thank you!
A better explanation, so detailed and well prepared you won't find it anywhere. Amazing
+chungaleta1234 Thanks for the feedback & pleased you found the video helpful. Cheers for now, Andy
Excellent, excellent, excellent! VERY well illustrated and explained. You, sir, Andy, stand amongst the 1% of instructors that truly CAN teach! Thank you for sharing!
Cheers for the feedback :-) Pleased I could be of help. Have a great day. Andy
Appreciate for the video sharing, it really helped me understand the very important point of the device, and how it works in the system, thanks again!
Keeping Andy mechanic alive is much more important than fixing cars!!! Great video ....keep it up!!!
Brilliant mate, yours is the best video, explanation with clear instructions anywhere. I followed your explanations, instructions and now my old Camry V6 (the YEAR 2000) is back to running smoothly and consistently idle, thank you
Yes i've been doing this befre for years.
So nice of you to share this iAcV mechanism., very much informative and detailed good for others to know.
i'll continue to watch this later, see you.
By far the best explanation of these gremlins I've seen so far!
Have cleaned this type of IAC on a Toyota in the past, but had no idea how it functioned. Took off the coil part, needlessly, and cleaned the rest of the carbon gunk. Congrats on giving an in depth explanation of how everything works. The art of teaching is not lost on you.
Andy you are amazing you have cleared many of my doubts and worries on IAC valve.Thanks a lot
You are the man Mr.Mechanic this is what we need thank you very much
Great video! It was amazing to actually see the idel control valve working on the mechanical side and electronic side!
I had some idle issues in my Corolla, and my mech replaced throttle body with an used one. The problem was fixed. During my leisure time and out of curiosity I decided to fix my old throttle body. The main valve opens and closes perfectly fine, so I opened the IAC valve that I learned from youtube. I found huge carbon deposits in there, I cleaned up all with a carburator cleaner. Then I supplied 12v using a power adapter, and found the IAC valve closes and then back opens immediately like a springy mechanism, like an electric calling bell. Yesterday I was searching hundreds of videos to check whether this is normal or not, but found nothing. Then today youtube suggested this video and now I understand the whole working mechanism of this IACV system. I can't thank you enough :). Now my only problem is the rubber gasket got bigger than it's normal size. Looks like I have to cut and join that using super glue to make that short. I'll also apply some RTV gasket sealer.
Wow, now he answered my question, I have my honda with similar but not exact iacv with the coolant lines disconnected and now I see where to begin with my idle issue. What a valuable information I got from this video.
Excellent explanation. Thanks to you, I understand that valve now and feel confident that I won't screw it up taking it apart to clean. Thank you
Thanks Andy, I had this problem after replacing my Toyota Wish 1ZZ FE engine and reused my old inlet manifold and throttle body. Today I managed to resolve my high idle speed by doing exactly what is in your clip.
A great teacher, tutor and mentor.
Amazing video solved my problem with Corolla thank you so much for your in depth tutorial and insight, very rare these days. A Bi-metal spring wow.
Great video ! I believe your customers really enjoy your auto mechanical service you done for them ! thanks lot !
Smart man. Even better an educator. Even asking to share utube so others may have their query satisfied
Keep doing the good work. This video has helped me alot.
just blown away by your explanation
just what i wanted to know, well presented ,many thank you's.
Exactly what i was lookin for, thank you so much man!
Very Detailed explanation. Great job!
You are indeed a great teacher!
Thank you sir Andy! More power!
Nice explanation. Good job.
This is what I was looking for so thanks so much! My 96 Honda Civic service manual doesn't explain jack about how this device works! They don't write em like they used to!
great video dude they didn't teach us about this in collage so really helpful and very well and clearly explained
Thanks David for your feedback, it's most welcome and helps give me the motivation to continue making the videos. I'm happy you find them helpful. Cheers Andy
Thank you ever so much for sharing your experience with us.have a Honda and that valve has been giving me hell.must information I have ever gotten on those valves , definitely subscribing....cheers
Dear Andy, explained well,got depth knowledge.
and enjoyed ur vedio.
Great video andy, very well explained, cheers from Ontario ca
Excellent video!
thats a great in depth explanation 👍
Brilliant explanation, cheers.
great video. very clear and informative. got enlightened with this one. God bless!
Excellent teaching, Andy!
Greetings from the U.S.A.
Subscribed!
Thanks James :-)
Thanks very much for Andy
Dude...you have a gift for teaching... great...great... great video!!!
Cheers Ed, appreciate your feedback. Have a great day. Andy
Thank you Andy very profesional just what i need. RSA
Better than the "Average Bear" can even attempt to explain. Am much older than you, but know excellent teaching skills when we see this. More like this? Bravo Mate! 😳
Thank you Andy Great lesson!!
Great instructions!
Nice excellent explanation about IAC I like
Is a solenoid valve with two magnetic fields.👍👍👍👍👍EXCELLENT VIDEO, very informative, accurate and verywell explained. 👍👍🇵🇷👍👍
Excellent video.. Very clear..
Great watching your videos
Thumbs up ! The best explanation
just caught your work. Got a subaru 93 and it quit idling on me. Gave me some good info. Thanks.
I had same problem with my 1991 Subaru Liberty. This is what I did: First, I disconnected both battery cables. I then disconnected Throttle Valve Sensor. I then took off the air supply to the throttle valve, you know the big round pipe. I then pushed the gas/petrol pedal to the floor and kept it there with a long stick against the car seat or you can put a heavy brick or other object against the pedal. Find a piece of 4mm thick masonite and cut to the following dimensions: 300mm(length) x 250mm(width). Attach a piece of lint free rag. Tie the rag on the masonite with a strong string. Spray ONLY throttle sensor cleaner on the rag and start cleaning throttle valve and the sides gently. Be careful you don't drop anything in the throttle valve barrel. It could end up on top of a piston. When rag is dirty replace with new one. Do not spray throttle sensor cleaner directly inside throttle valve area. When you finish cleaning take the pedal stick away, reconnect the throttle valve sensor, then reconnect Battery ( + ) cable first and then Battery (-) cable. Reconnect air supply pipe and hoses that you may have taken off to help you to access the throttle valve. Start your car and let it idle until engine is warm. The ECU may need a few days driving to adjust to the new settings. Before you start have a look at some RUclips videos to understand how to clean the Throttle Valve. Some videos are on Subaru throttle valves. If cleaning the throttle valve doesn't help then you might need to go for the Idle Speed Control Valve. I haven't tried cleaning that yet. There is more involved with taking that off and cleaning it. You will need to disconnect and block coolant hoses. Good luck. My car used to stall at lights or as I was driving along. I then started again go 50 metres and then it would stall again. My mechanic tried to fix it twice but was unsuccessful. I'll never go to him again.
hi andy ,great info & more important delivered easy style ,great work ,left in no doubt of i.a.c. funtion much obliged
awesome vid bro. thanks a lot.
Excellent teaching
+Doug Jones Thanks :-)
what a very nice explanation about the principle operation of aicv, i subscribe for more man! more power!👍😀
Excillent, helpful, thanks brother
You are simply the best
just brilliant A clear explanation
any isc valve i removed needed a IMPACT SCREW DRIVER YOU GOT LUCKY thanks from new york city USA.
+MrRobert1603 Haha! Yes, you are probably right! Pleased you liked the video & Cheers for the feedback. :-)
Man .. This was beyond amazing and interesting video I enjoyed watching it. Can you please make other videos about other types of IACV's, also about other sensors dismantling and testing? .. Cheers.
thank it was very help full
Thanks man. The best video online that teach how IAC valve works. I'm lucky you explaining it on Toyota.
Cheers :-)
Andy Mechanic sorry for bother you. I have corolla 2007, 2 years ago I took the iac valve apart to clean while I was cleaning the throttle body. I don't remember when the current rough idle started, now the car idle is rough, when i engage the AC, the idle shakes a lot. But when it's cold, the idle is great, but immediately after few minutes when the car gets hot, the idle is rough and the rpm drops to 730 to 750.Someone told that i might have messed up the factory calibration when i took it apart. But since i had no clue, i don't remember anything when i took it apart. What do you suggest and think? Thanks
@@AndyMechanic I tested the resistance of the coil and one side gives me 19.8 kohm, but the other 47.2 kilo ohm. I did your visual test and made a circuit and doesn't open at all even though the RSO resistance is 19.8 but still doesn't open at all. the RSC does even close and has resistance of 47 kohm. what do you think?
The primary side of the coil should have low resistance (thick wire, few turns) the secondary winding high resistance (thin wire many many turns) - it looks like your coil is faulty...
Andy Mechanic thanks for the reply. First what do you mean by primary and secondary winding?. Secondly, But I'm wondering if it's faulty why it doesn't trigger check engine sign?
If you can find an IAC noid light, it makes for a great little disco light on a properly functioning system!
It was really neat seeing this rotary style IAC taken apart! I had no idea they had an entirely mechanical fast idle like that. Cool! :D
Thanks rhkips for your feedback, I'll most likely be making some more videos covering other types of IACs at some point too :-)
Awesome, well done, thx!
I see a lot of channels saying it fixes idle.. yes it does but it also can fix idle + hesitant acceleration, so drive ability as well
You are the best .... thank you sir
Very helpful!
Excellant discription
very interesting thank you
Great breakdown. In other people's advice on this part, they have discused diagnosing through a use of an underhood diagnostic box, where you can jumper across a terminal, and the rpm should increase, which I guess means it is signaling the IAC to open? So it must be a jump of ground to the RSO terminal?
great info
Good job mate.
Cheers & thanks for the feedback. Andy
Really really you are a creator
Yo u are good bro keep it up
Great video! Was going to comment about how slow you get to the point
But it was well worth the 5 minute introduction.
Excellent video..how technical video's should be made..❤
thank you
Very informative. Thanks, Andy! subscribe and like
Hello Andy, I was wondering, I checked my isc valve yesterday. I checked it with a 12v supply. The solenoid worked only in one direction but not the other. I didn't check the ohms of the circuit. Do you recommend I do this test before I say it's dead and need to replace it. Also could there be a build up of carbon and other debris and rubbish in there could could be affecting the operation of the solenoid. Thanks for your help. Much appreciated. Just so you know which you probably already do, but the RAV4 and MR2 have the same engines in and you can download the bgb off the internet which is a complete break down of the 3stge engine. It's a 1500 or so page workshop manual.
Thank you very much for this detailed video. I have a trouble shooting on iac valf of Toyota corolla ae101 4 afe . I cleaned the throttle body and replaced it. But idle speed is little bit high, the speed is 1250 in minute . On lpg is normal but when I activate the fuel benzine is 1250 rpm in one minute. I touched the iac valve shaft during the cleaning it. Please tell me which side I should adjust the idle shaft for regular position left or rihgt side thank you very very much for help.
Very very good video….If my 2002 Toyota is idling high at 2000 rpm would the little door be fully open
Nice!
Do you have to drain the coolant before removing the IAC valve? (I have a 2001 Toyota Camry.)
Andy! MAYDAY! Lol. My 2006 corolla idles fine when cold but once the engine is warm, the idle drops and feels as if its going to stall when stationary. When i turn on the AC or Lights etc., the idle increases. Could it be that the iac valve is the culprit?
Mr please help me to know if throttle valve is bad because it doesn't closed properly
i see the valve is slightly open on the closed side. is that normal or should it be fully shut? cheers
In my case, only one of the ground reacts when i connect it to a ground source. Does it mean it is broken?
If the engine doesn’t idle less than 1200rpm. Does it mean that when I reassembled the valve I was a bit off with the valve plate?
I moved the adjustment screw on the accelerator until it makes no difference on the idle speed. It started at 1500rpm wanted to take it down to around 800 to 1000rpm.
Any suggestions?
How do the Engine Coolant Temp Sensor and this Idle Speed Control Valve relate to idle speed? On a Camry 1mzfe the ECT sensor reads at the outlet if temp is up ECU should drop idle speed vise-a versa. To drop the speed, do the ISCA receive an influence from what the ECT read? I understand the ISCA also reads the temp from inlet temp before the thermostat valve to influence the the ISCA bi-metallic coil. Is either one more dominate?
What is possibly keeping the idle high at 1400rmp if the ECT sensor outlet and ISCA are already at Operating Temp? I got a new OEM ECT Sensor. Occasional, 400rmp made me change the ECT sensor. And idle would drop from 1100 to 400rmp if the old ECT Sensor was disconnected but there is no change if the new ECT Sensor is installed.
I hope I didn't missing something in your great explainable video.
Sir, what is the function of the vacuum pipe outlet on the IAC? where it connects to?
How can I adjust cold start idle? It reaches 1800 rpm. It was previously adjusted when my mechanic tune up my car but he did not found a very hi rpm during cold start bec he tune while in normal operating temp. Please show me how and where to adjust my IAC for my 4AFE engine.
Enjoyed the video! Nicely done., very detailed and well explained operation of these little devices. I have toyota which has sat for a while. It starts and runs well wit throttle open but at idle stumbles to a stop like choking itself to a stop. I have cleaned and loosened this valve as it was stuck but still have the problem. Any suggestions?
Hmmm....could be a few things, have you checked fuel pressure & quality? Fuel can go off over time so maybe drain the tank & give it some fresh fuel, just to eliminate that possibility
Other than that I'd test map sensor & check all the vacuum pipes as these perish over time.
Hope this helps. Cheers Andy
Sir, what is PWM idle control valve??
My car i20 1.2 petrol has 3 pins connector to its idle air control valve. Pin 2 gives 12.6 v when grounded. However, pin 1 and 3 gives only about 10.5 V when measure with respect to positive post of battery. Why I'm not getting 12.6 V???
Also, very surprising is that, when pin 1 and 3 are grounded individually, they still give about 1.5 volt. Is there something current nor voltage leaks??? Our main issue is pin 1 and 3.
Please find me solutions!! Thanks.
My Toyota 7K-E often gets the rpm swing between 1000 to 2000 after a long run and then lets off the gas pedal. Do you have any idea what happened?
Hi Andy, this is good stuff! Just a quick question though... when you removed the isc motor from the housing, is the sealant orignal from the factory? Thank you
Golly, sorry, it was a few years ago & I can't be sure.
Andy
May I ask if I attempt to clean my ISC valve due to dirt is there any effect will have on the ecu? Thanks mate!
No. Just disconnect & you'll be just fine :-)
The part about the duty cycle is what surprised me. That being said, I tested the signal coming to the ISC connectorand I only get a solid reading of above 12V on the RSC pin (uppermost pin from ground) to the center B+ pin (battery positive) and I'm wondering what could cause that?
If this is "duty cycle", I'm assuming there's signal going to both ground pins and the computer is varying it according to the needs of the motor like you said. I'm guessing the RSO (Lowest pin) should have some larger value of voltage than the RSC pin when starting cold. The reason I say that is when I connected just the RSO pin as ground with 12 volts positive to the B+ pin with a jumper cable, it idles high like it should when the engine is cold.
When testing with a multimeter, the RSO pin voltage shoots up to 9V and then drops immediately w/o me doing anything when the ignition is in the ON position w/o starting it. I double checked this by using a computer from an old same model car (Toyota Previa) I had, and the same 9v initial voltage jump happened and went back to 0.
Whoever is reading this, if you're idle is working correctly, taking this reading would only take a few minutes and would help me tremendously.
Maybe when I fixed my MAF awhile back (apparently the solder joints are temporary - ruclips.net/video/CXCpYj-r_lI/видео.html) I soldered something that now is causing this problem...hmm....still thinking about that one...
The grunge inside the water section can be removed by radiator flush fluid, without removing the valve from the throttle body.
Hi dose the water flow makes a difference