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2003 CTS 3.2
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Discussion Starter · #1 ·
Okay I've been around the block a few times and I've built cars from the ground up before but this is my first interaction with a Cadillac. It's a 2003 Cadillac CTS 3.2 l luxury sport rear wheel drive The onboard diagnostic computer in the stereo told me it had a bad IAC. But I've been told there is no idle air control valve on this car how could it say IAC valve needs servicing across the stereo screen when it doesn't have one ? I know it has a misfire on some of the three and five and I'm going to replace spark plugs and coils on both sides but it says idle air control valve malfunctioning why would it say that if it doesn't have one?
 

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2005 CTS 2.8L
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800 Posts
It does have an IAC but it is part of the throttle body and not sold separately. I just replaced mine recently on my 2005 cts. You might try removing the throttle body and cleaning everything real good and then see if the message goes away otherwise you will probably have to buy a new one.. Here is a link and you scroll to the bottom of it and it tells you that the throttle body comes with the idle air control valve.


Roy
 

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2003 CTS 3.2
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34 Posts
Discussion Starter · #3 ·
Just my luck I'd have to replace an entire throttle bodyI'll I'll try cleaning it first really well because I have to take it off anyway cuz I'm replacing all the spark plugs and coil packs on both sides because it does have a misfire on cylinder three and five. I'm a pretty good mechanic but this is my first Cadillac so wish me luck I hope it isn't The money pit I've been reading about cuz it is a running son of a bitch you couldn't tell anything was wrong with it while you're driving it except for when you're at a stop and it tries to stall out and die and the check engine light flashes and the codes tell me it's a misfire
 

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2003 Cadillac CTS
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362 Posts
It's a generic OBD2. They wouldn't take the time to personalize it because it was never intended for use by the owner/driver, but by a mechanic...at a Cadillac dealer. They nixed it the very next year because all of the people that found out and then used the built-in OBD2 reader was bugging them to death over BS pending codes.

...So I've heard...twice...

...Ok...

Am I wrong in thinking that this would be the or within the air intake resonator? It's the convoluted black plastic ductwork, in the shape of a 2 ft "W", after the air filter but before the throttle body (The explanation is for a noob that maybe reading in the future)? The air valve at it's center?

Coming to think about it... Try a throttle body relearn. It could also be considered an idle relearn.

Cut n' Paste of the procedure:



Idle Learn Procedure

The engine control learns the idle position of the throttle body for correct operation. When the throttle body or ECM is replaced, this procedure must be performed to ensure correct idle operation. The engine idle may be unstable or a DTC may set if the idle position has not been learned. Perform the following procedure in order to allow the ECM to learn the idle position:

1. Ensure that the following conditions are met:

* The vehicle speed is 0 mph.

* The accelerator pedal angle is less than 14.9 percent.

* The battery voltage is more than 10 volts.

* The engine coolant temperature (ECT) is between 5-60°C (41-140°F).

* The intake air temperature (IAT) is between 5-60°C (41-140°F).

2. Turn OFF the ignition for 30 seconds.

3. Turn ON the ignition, with the engine OFF for 1 minute.

4. Turn OFF the ignition.

5. Turn ON the ignition, clear codes if required.



Give that a go and get back with us.



It does have an IAC but it is part of the throttle body and not sold separately. I just replaced mine recently on my 2005 cts. You might try removing the throttle body and cleaning everything real good and then see if the message goes away otherwise you will probably have to buy a new one.. Here is a link and you scroll to the bottom of it and it tells you that the throttle body comes with the idle air control valve.


Roy
Decent price for an ACDelco


Does anyone know exactly where it is within the throttle body? Can it be excised and reinstalled? Soldered off and on maybe?

I replaced mine a couple months back when it couldn't read where the butterfly was. I still have my old one.

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2003 CTS 3.2
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34 Posts
Discussion Starter · #6 ·
I have watched videos on replacing the spark plugs and coil packs and intake gaskets on the 2003 Cadillac CTS with a 3.2 l. What is that plastic piece that is on top the motor that has two lines going in the front on the throttle body and four lines coming out through the back I know it's part of the vacuum for what is it called and can I order it to replace it cuz it looks like it'd be very hard to clean and it says they had to redrill the holes in the bottom of it so I might as well just replace the thing but I don't know what it's called and I can't find it anywhere in any diagram.
And furthermore I have found another post that says there is an idle control valve on this 3.2 l 2003 Cadillac CTS it is underneath the intake in the rear and they even sent a link with the picture of it so to the person who said that there is no out of control valve you're wrong because my car radio told me I will control valve needs repaired why would it say if it didn't have one
 

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2003 Cadillac CTS
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362 Posts
The black plastic piece stop the engine is half of the poorly designed PCV system on the '03's. If the modifications haven't been done go ahead and do it.


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2003 CTS 3.2
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Discussion Starter · #8 ·
Thank you for your best response. But in the video it showed the guy had a ton of carbon buildup inside his can't I just order that plastic piece that goes across the top of the motor? Or do I just have to drill out the holes and clean it myself. And do you know if the throttle body is also part of the idle air control valve or if there is actually an idle air control valve under the intake on the back of the motor as I was told on another form because I can't seem to find one you have my onboard computer told me it was bad
 

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2003 Cadillac CTS
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Thank you for your best response. But in the video it showed the guy had a ton of carbon buildup inside his can't I just order that plastic piece that goes across the top of the motor? Or do I just have to drill out the holes and clean it myself. And do you know if the throttle body is also part of the idle air control valve or if there is actually an idle air control valve under the intake on the back of the motor as I was told on another form because I can't seem to find one you have my onboard computer told me it was bad
That part has been discontinued. Along with the PCV upgrade kit. You will run into discontinued parts a lot on the '03 CTS...it sucks. No worries though! They're easy to clean and there's many instructions and tutorials on this site and YouTube.



Most likely, the part pictured below is what you're looking for on the back of the intake. It's a Intake Tuning Valve. GM Part #12575129. It fine tunes the airflow when needed.


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2003 CTS 3.2
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Discussion Starter · #10 ·
Thank you very much I'll keep an eye out for it when I take the intake off. I wouldn't have so much time and money into it except even within having any problems as it does right now it's still a mean ass car. And I thought Cadillacs were old man cars this thing is a sports car true and blue
 

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2003 CTS 3.2
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Discussion Starter · #12 ·
Once you get it's issues ironed out, it'll truly be your Cadillac.

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thanks / im taking off the intake and replacing both coiul packs and all spark plugs , " IAC valve if i can locate it " clean and drill the vacuum ports to the new corrected 5/32 diameter . replace the thermostat while im there and all gaskets . hopefully that fixes the misfire . It only stalls and misfires when stopped .
 

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2003 CTS 3.2
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Discussion Starter · #13 ·
The black plastic piece stop the engine is half of the poorly designed PCV system on the '03's. If the modifications haven't been done go ahead and do it.


Sent from Earth II using Tapatalk V
mine has 2 hoses going in the front of the intake and 4 comiung out the back . and there is steam coing from out the front of the pcv pl;astic piece . noty alot but it smells like its burning oil
 
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