LS Idle Air control valve

lonestarlslover

lonestarlslover

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Have an issue with the power staying hot to the idle air control valve when the ignition is turned off , running down the battery and burning up the idle aie control value ........ Any idea's as to why ? Maybe a fix too ? ..... lol
 
eL eS said:
nt certain if I understand can you restate the problem/condition.
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When the car is shut off, there is two wires going to the idle air control valve, the power is still going to it when the car is shut off, holding the valve open, and the valve gets real hot to the touch, running the battery down and burning the , i guess cylinoid is whats burning up, if you look at the valve you'll see what i;m talking about, its the part the wires plug in too. and when running the car has a real rough idle and it hesitates real bad.
 
eL eS said:
have you replaced the IAC?
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Yes, but thats not the issue, the hot wire going to it is , it stays hot and burns the IAC valve up, or runs the battery down if left for a day or two
 
I have not seen this before. I do know that the LS' PCM is designed to keep power to the car for upto 15 minutes if I remember correctly.

They did this so that the computers would be more ready to start the car if the driver returned within that interval. I think it is more to deal with teh AF mixture os a hot car.

But it is would be hard to tell if the pcm is creating this without direct observation and pinpoint diag testing.

I would pay the 80 to 100 dollars and have the dealer diag this problem. It might end up being some thing simple and yu can take you car and do the repair at home.
 
eL eS said:
I have not seen this before. I do know that the LS' PCM is designed to keep power to the car for upto 15 minutes if I remember correctly.

They did this so that the computers would be more ready to start the car if the driver returned within that interval. I think it is more to deal with teh AF mixture os a hot car.

But it is would be hard to tell if the pcm is creating this without direct observation and pinpoint diag testing.

I would pay the 80 to 100 dollars and have the dealer diag this problem. It might end up being some thing simple and yu can take you car and do the repair at home.
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hey mom , send money ! .......... lol
 
That is very, very strange. I've never heard of this before. Since the ECM controls the IAC, I would guess that is where to start. I don't believe there is a relay involved, but I would need to look at my wiring diagrams to be sure. If so, that should be the culprit. I think the first test I would make would be to disconnect the ECM and see if the power dies at the IAC. If not, then there is either a short to power in the harness or a relay. If it does, I would suspect the ECM. This should be solvable by close scrutiny of the wiring diagrams. Very weird.
 
2001LS8Sport said:
That is very, very strange. I've never heard of this before. Since the ECM controls the IAC, I would guess that is where to start. I don't believe there is a relay involved, but I would need to look at my wiring diagrams to be sure. If so, that should be the culprit. I think the first test I would make would be to disconnect the ECM and see if the power dies at the IAC. If not, then there is either a short to power in the harness or a relay. If it does, I would suspect the ECM. This should be solvable by close scrutiny of the wiring diagrams. Very weird.
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This would make sence , could you do that please, I dont have a wiring diagram, nor do i know where to find the ECM to unplug it. Any help you could give would be great. thanks
 
Not many of us have the electrical diagrams and what you are looking for is very difficult without direct observation. I'll be the first person to take this advice becasue I have done; you really should take this one to the dealer. Electrical issues are the most difficult problems to ferret out on this car due to its complexity. The stakes are too high on this problem to approach it casually.
 
eL eS said:
Not many of us have the electrical diagrams and what you are looking for is very difficult without direct observation. I'll be the first person to take this advice becasue I have done; you really should take this one to the dealer. Electrical issues are the most difficult problems to ferret out on this car due to its complexity. The stakes are too high on this problem to approach it casually.
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Sounds like the ECM , and if i knew where it was, maybe i could do the little test the other poster sugjested, But sounds like in the end it will see the dealer.... thought maybe there was something simple, should have know, nothing is simple, lol Thanks for all your help !
 
The problem is that there are numerous computers that control a multitude of functions. I can think of 4 just off the top of my head and I think there might be as many as 6 or 7 computers.

I know what it is like to be up against the wall and to have this car speeding towrds you. Not to brag but I do pretty well and this car nearly busted my bank account as recent as a year ago.

I troubleshoot what I can and carry otu the repair and if i cannot not find the problem I will take it to the dealer and carry out the repair. worst case is to let them do both.

If you can get to what the problem is we will be here to help you decide if ti is something you want to do on your on. Possibly find someone near you to help out. I have extended the offer to Tampa area LS owners and the offer still stands today.

Dealers hardly care about you if you are paying out of pocket and even less if it is under warranty so I have very little respect for their establishments. I have nedured too much guess work repair service to take it and to have other take it if I h\can help.
 
the PCM is behind the glove box. If you have a multi meter you could start by turnig teh car off wait 15 minutes so that all teh computers will shut down and then hit the fuse boxes with the multimeter to see where the power is drwaing from. It could be one system it could be multiple. Id the fuse and you might be on your way to solving the problem. Again these types of issue are hardly easy to solve.
 
Sorry it took so long to get back to you. It looks like it's powered from the Auxillary Junction Box under the hood. It makes a difference on your build date as to how it's wired. If before 9/29/2000, it's powered by fuse # 105 (20A) which is also tied to the hydraulic fan control solenoid. If after that date, then it's powered by fuse # 110 (5A). Early build is a 16 gauge wire that is Green w/yellow and late build is a 20 gauge that is orange w/yellow. I see no relay in the picture...so you must be looking at a short somewhere.

Can someone take a test light to one of their vehicles (I don't have access to my son's right now) for us and see if this fuse (whichever circuit your build date requires) is powered up with the key off? If not, then you know that you are picking up power from somewhere and need to find the short to power. If it is powered with the key off, then it looks like the ECM grounds the circuit and it is probably the culprit. But before I condemned it, I would disconnect the ECM and see if the draw goes away. If it does, then you have a safe bet the ECM is bad. If it doesn't, then you must have a short between the ECM and the IAC motor. This shouldn't be that hard to diagnose knowing what you do now. Fixing it may be a bitch though!! LOL
 
2001LS8Sport said:
Sorry it took so long to get back to you. It looks like it's powered from the Auxillary Junction Box under the hood. It makes a difference on your build date as to how it's wired. If before 9/29/2000, it's powered by fuse # 105 (20A) which is also tied to the hydraulic fan control solenoid. If after that date, then it's powered by fuse # 110 (5A). Early build is a 16 gauge wire that is Green w/yellow and late build is a 20 gauge that is orange w/yellow. I see no relay in the picture...so you must be looking at a short somewhere.

Can someone take a test light to one of their vehicles (I don't have access to my son's right now) for us and see if this fuse (whichever circuit your build date requires) is powered up with the key off? If not, then you know that you are picking up power from somewhere and need to find the short to power. If it is powered with the key off, then it looks like the ECM grounds the circuit and it is probably the culprit. But before I condemned it, I would disconnect the ECM and see if the draw goes away. If it does, then you have a safe bet the ECM is bad. If it doesn't, then you must have a short between the ECM and the IAC motor. This shouldn't be that hard to diagnose knowing what you do now. Fixing it may be a bitch though!! LOL
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This is what i have so far, But its not making much sence .... lol I have a bulid date of 12 99 and an orange w/yellow wire and it has an in line 5A fuse. I pulled the fuse and the IAC stops humming, its hot all the way to the fuse box ....... Now what ? lol
 
2001LS8Sport said:
Sorry it took so long to get back to you. It looks like it's powered from the Auxillary Junction Box under the hood. It makes a difference on your build date as to how it's wired. If before 9/29/2000, it's powered by fuse # 105 (20A) which is also tied to the hydraulic fan control solenoid. If after that date, then it's powered by fuse # 110 (5A). Early build is a 16 gauge wire that is Green w/yellow and late build is a 20 gauge that is orange w/yellow. I see no relay in the picture...so you must be looking at a short somewhere.

Can someone take a test light to one of their vehicles (I don't have access to my son's right now) for us and see if this fuse (whichever circuit your build date requires) is powered up with the key off? If not, then you know that you are picking up power from somewhere and need to find the short to power. If it is powered with the key off, then it looks like the ECM grounds the circuit and it is probably the culprit. But before I condemned it, I would disconnect the ECM and see if the draw goes away. If it does, then you have a safe bet the ECM is bad. If it doesn't, then you must have a short between the ECM and the IAC motor. This shouldn't be that hard to diagnose knowing what you do now. Fixing it may be a bitch though!! LOL
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I opened the fuse box to see where thar wire goes and it bolts directly to the main battery lead that comes into the fuse box, so i'm guessing it is suposed to be hot ? thats a guess ....lol or is some thing else not right, should the main power to that fuse box under the hood shut off with the key ?
 
After doing some more looking at the wiring diagrams, fuse 110 (5A) and the one that powers your IAC is ALWAYS powered. Very strange. The other wire in your IAC connector is the ground which goes to the ECM for control. I still think this is fairly easy to diagnose with a little time and effort. Since it looks like the IAC is constantly powered, it has to have a ground to operate. From what I see, the ECM controls the ground to run the motor. So if it's constantly being activated, it is grounding somewhere. Let's take a look at a couple of things and see if we can't isolate where the ground is. The first thing I would do is remove the connector from the ECM. If your IAC quits being activated, then I would assume it's a safe bet you have a bad ECM. However, it is very rare for an ECM to go bad, so be prepared to start looking elsewhere. If disconnecting the ECM does NOT fix the problem, disconnect the harness connector at the IAC and run a 12V power supply (jumper wire) to the power side pin of the IAC. If the motor starts activating without a ground hooked up like that, then the short is in the IAC itself. If not, then the short is in the harness between the IAC and the ECM. That could be a real bitch to find. If that's the case, you could always run a new wire and splice and solder it in between the IAC motor and the proper pin on the ECM. This is pin #9 on connector C175C if it helps.

Stay with this and let us know what you find!
 
IIRC the LS uses ground switching so this may explain the always hot. disconnecting the ground is a good idea as you stated that would indicate a short if the problem persisted.

Good job looking out for him 01LS8.
 
lonestarlslover said:
hey mom , send money ! .......... lol
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A Ford dealership could do the same diagnosis for $50. Autozone can give a you the computer error code for free.
 
They are trying to find a wiring fault. This has progressed from just needing a DTC. FLM usually has a base of 90 bux to do a diag probably even if it were to scan a DTC. I used to use you AZ no complaints but I found that I needed a scantool of my own that could get the Ford codes stored for the numerous systems not covered in the obdii spec.
 
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