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Discussion Starter · #1 ·
2005 ZX4 5-speed 2.0L Duratec PZEV 194K DTC P2004

This is the engine with the single intake manifold actuator and vacuum control solenoid. The actuator does not move - at least revving the engine in neutral. Ive tested the actuator by by manually moving it and connecting it to a mity vac vacuum source and it and the runner flaps moves freely and the actuator holds vacuum. Ive also tested the vacuum hoses from/to the vacuum solenoid and they are fine - hold vacuum and no cracks, etc. So this leads me to surmise that the issue is the vacuum solenoid itself which Im planning on replacing. I havent removed it to bench test it yet because its a little bit of a PITA to get at. Other than the DTC/CEL and a bit of a initial high idle when first started and sort of almost wanting to stall when coming to stop (it doesnt) it still runs fairly well.

I was just wondering if anyone know under what running conditions the solenoid would be active and the actuator actuated?

Thank you
Paul
 

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I know it is a 2.3 Paul but there is some good testing information in the above thread. I have no idea what rpms the imrc system operates at.
 

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Discussion Starter · #4 ·
I think I understand what Marde was getting at in that thread: that another cause of the P2004 could be a failure of the actuator sensing circuit - which I will try to test. According to the schematic the actuator has three wires going to it: power, sig rtn (to PCM), and IRMC monitor (also to PCM). I would think that the three wires are connected inside the actuator in some way when at rest (no vacuum) and in a different way when the actuator is actuated (by vacuum) signalling the PCM that it has moved.

Thank you for your input!
Paul
 
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I think I understand what Marde was getting at in that thread: that another cause of the P2004 could be a failure of the actuator sensing circuit - which I will try to test. According to the schematic the actuator has three wires going to it: power, sig rtn (to PCM), and IRMC monitor (also to PCM). I would think that the three wires are connected inside the actuator in some way when at rest (no vacuum) and in a different way when the actuator is actuated (by vacuum) signalling the PCM that it has moved.

Thank you for your input!
Paul
You're welcome. Dennis
 

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Discussion Starter · #6 ·
From
You're welcome. Dennis
Dennis,
From what I have been able to tell the actuator should be actuated (flaps closed) at idle and low RPM. Now obviously my actuator is not moving (closing) at all. So as previously discussed it could be the vacuum solenoid that supplies vacuum to the actuator has failed or its not getting a signal from the PCM because the actuator sensing circuit has failed. I will try to bench test to solenoid.

Thank you again
Paul
 
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Discussion Starter · #7 ·
Marde,
I see you are following this so thank you for your post on this subject from 2014.

All,
I found this video very helpful/informative (although they did not address the sensing circuits and have the code descriptions backwards):

Paul
 
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Just for the sake of guesses and silly percentages... here is what usually causes the DTC P2004:
45% of the P2004 failures are due to cracks within a vacuum hose; between IM to Solenoid OR between Solenoid to Actuator.
45% of the P2004 failures are due to a failed Solenoid.
The remaining 10% are a failed Actuator or a wiring defect between the Solenoid or Actuator that interconnect to the PCM. An extra bonus 1% are left for space alien magic electrical attacks.

I think I understand what Marde was getting at in that thread: that another cause of the P2004 could be a failure of the actuator sensing circuit - which I will try to test....
Glad to hear you're able and willing to do that set of tests for the actuator electrical Input/Output (I/O). I doubt that test is needed, but I always encourage anyone & everyone to dive into that type of analysis and troubleshooting. BTW, I have not done the Actuator I/O meter (DMM) tests ever.

I would think that the three wires are connected inside the actuator in some way when at rest (no vacuum) and in a different way when the actuator is actuated (by vacuum) signalling the PCM that it has moved...
The IMRC/IMTV actuator is a variable resistor (Please see NOTE at the end of this post): Pin-1 is the "wiper". Pin-3 is Vref (+) and pin-2 is Vref (-) or it is directly connected to ground-> depends on the car year and configuration.

If the actuator is electrically connected, you can "multi-meter back-probe" Actuator Pin-1, and measure a voltage change when the Actuator Arm is Up verses Down.
Actuator Arm is Down = system is On and is working correctly. Flaps are Closed. This happens at engine idle, and it stays in this mode for engine RPM ~2400 and under.
Actuator Arm is Up = system is Off. Flaps are Open = this happens at about engine ~2500 RPM and above.

Marde,
I see you are following this so thank you for your post on this subject from 2014...
Huh? How'd ya know I read ur new thread? I did quickly read it earlier today, but I was too busy at that time to reply then. Like you guys, life, work, and kids get in my way to post here at FF.

All,
I found this video very helpful/informative (although they did not address the sensing circuits and have the code descriptions backwards):
I did open that link, that video, and it was kinda painful to watch it. I almost bailed out during the first 2 minutes. Very glad I hung in there and watched the whole thing. I heard the younger guy say something that was obvious to me as FALSE. However.... About half or 3/4 way-through-it, I realized that they identified something very NEW to me. IF what they say is correct (( I believe it is )) their info is a huge LIGHTNING BOLT for me, and a huge learning lesson for other peeps here too. It is amazing that I have been so IMRC dumb or ignorant for so long.

This VIDEO lesson is two-fold. If true, the implication & my new understanding is big news to the FF community.

What are the IMRC flaps? I believe these are the flaps located near the bottom of the IM and these are only available on the 2.3 engine IM (correct?). As the name implies, IMRC changes the IM runner length.
What are the IMTV flaps, aka swirl flaps? I believe these are the flaps located at the top of the IM and are near dead-flush to the engine intake (correct?). These flaps are included in the 2005, 2006, 2007, is this correct?

When the 2004 2.3 engine (it has both IMRC and IMTV) -OR- when a 2005 2.0 car posts a P2004 code the Scan Tool will say "IMRC" failure. This is now (apparently) incorrect!!
When my (2.3) or your (2.0) car posts a P2004 code, it is NOT the IMRC, but it is actually the IMTV system that has failed.
The firmware inside of our PCM, inside of my car & inside of your car, is lying to us, and our MANY different types of scan tools are forced to lie to us because of our PCM firmware.

You have a P2004 IMRC code ONLY BECAUSE the scan tool is saying it is IMRC. Despite the scan tool saying P2004 = IMRC, the actual fault is caused by the IMTV system. This is ground breaking news for me, and for many other & most all of the older threads too. Those that say P2004 = IMRC are correct ONLY because that is what the scan tool says. The P2004 is actually a IMTV fault. This is true... until other contradicting facts trickle in... TBD.


NOTE: "The IMRC/IMTV actuator is a variable resistor": Because of the NEW NEWS, it is odd to say that the IMRC or the IMTV has a internal variable resistor. To lessen the confusion, let's please agree to say that only ONE of the two actuators has an electrical connector. Whether you call it the IMRC Actuator or the IMTV Actuator, only ONE of these has an internal variable resistor for the PCM to monitor its' physical position. For now, and until other facts come to light, let's just say (based on ALL older info) the IMRC Actuator is the one with an electrical connector and is the only one with the internal variable resistor + this is the only actuator installed on a 2005, 2006, 2007.

You're welcome. Dennis
Holy cow! pbfoot has a hidden nick name = Dennis.
Hello Dennis. My hidden nick name is Marty.
 

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Just for the sake of guesses and silly percentages... here is what usually causes the DTC P2004:
45% of the P2004 failures are due to cracks within a vacuum hose; between IM to Solenoid OR between Solenoid to Actuator.
45% of the P2004 failures are due to a failed Solenoid.
The remaining 10% are a failed Actuator or a wiring defect between the Solenoid or Actuator that interconnect to the PCM. An extra bonus 1% are left for space alien magic electrical attacks.


Glad to hear you're able and willing to do that set of tests for the actuator electrical Input/Output (I/O). I doubt that test is needed, but I always encourage anyone & everyone to dive into that type of analysis and troubleshooting. BTW, I have not done the Actuator I/O meter (DMM) tests ever.


The IMRC/IMTV actuator is a variable resistor (Please see NOTE at the end of this post): Pin-1 is the "wiper". Pin-3 is Vref (+) and pin-2 is Vref (-) or it is directly connected to ground-> depends on the car year and configuration.

If the actuator is electrically connected, you can "multi-meter back-probe" Actuator Pin-1, and measure a voltage change when the Actuator Arm is Up verses Down.
Actuator Arm is Down = system is On and is working correctly. Flaps are Closed. This happens at engine idle, and it stays in this mode for engine RPM ~2400 and under.
Actuator Arm is Up = system is Off. Flaps are Open = this happens at about engine ~2500 RPM and above.



Huh? How'd ya know I read ur new thread? I did quickly read it earlier today, but I was too busy at that time to reply then. Like you guys, life, work, and kids get in my way to post here at FF.



I did open that link, that video, and it was kinda painful to watch it. I almost bailed out during the first 2 minutes. Very glad I hung in there and watched the whole thing. I heard the younger guy say something that was obvious to me as FALSE. However.... About half or 3/4 way-through-it, I realized that they identified something very NEW to me. IF what they say is correct (( I believe it is )) their info is a huge LIGHTNING BOLT for me, and a huge learning lesson for other peeps here too. It is amazing that I have been so IMRC dumb or ignorant for so long.

This VIDEO lesson is two-fold. If true, the implication & my new understanding is big news to the FF community.

What are the IMRC flaps? I believe these are the flaps located near the bottom of the IM and these are only available on the 2.3 engine IM (correct?). As the name implies, IMRC changes the IM runner length.
What are the IMTV flaps, aka swirl flaps? I believe these are the flaps located at the top of the IM and are near dead-flush to the engine intake (correct?). These flaps are included in the 2005, 2006, 2007, is this correct?

When the 2004 2.3 engine (it has both IMRC and IMTV) -OR- when a 2005 2.0 car posts a P2004 code the Scan Tool will say "IMRC" failure. This is now (apparently) incorrect!!
When my (2.3) or your (2.0) car posts a P2004 code, it is NOT the IMRC, but it is actually the IMTV system that has failed.
The firmware inside of our PCM, inside of my car & inside of your car, is lying to us, and our MANY different types of scan tools are forced to lie to us because of our PCM firmware.

You have a P2004 IMRC code ONLY BECAUSE the scan tool is saying it is IMRC. Despite the scan tool saying P2004 = IMRC, the actual fault is caused by the IMTV system. This is ground breaking news for me, and for many other & most all of the older threads too. Those that say P2004 = IMRC are correct ONLY because that is what the scan tool says. The P2004 is actually a IMTV fault. This is true... until other contradicting facts trickle in... TBD.


NOTE: "The IMRC/IMTV actuator is a variable resistor": Because of the NEW NEWS, it is odd to say that the IMRC or the IMTV has a internal variable resistor. To lessen the confusion, let's please agree to say that only ONE of the two actuators has an electrical connector. Whether you call it the IMRC Actuator or the IMTV Actuator, only ONE of these has an internal variable resistor for the PCM to monitor its' physical position. For now, and until other facts come to light, let's just say (based on ALL older info) the IMRC Actuator is the one with an electrical connector and is the only one with the internal variable resistor + this is the only actuator installed on a 2005, 2006, 2007.


Holy cow! pbfoot has a hidden nick name = Dennis.
Hello Dennis. My hidden nick name is Marty.
Lol. Thanks Marty.
 

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Discussion Starter · #12 ·
Just following up on this. After having a CEL with a P2004 for about a week or so the CEL went out a few days ago on its own. I had been planning to bench test the vacuum solenoid when the problem resolved own its own. The CEL is out and the IMRC actuator is now actuated at idle (which it wasnt before when I had the CEL). My understanding is it should remain fully actuated below 2500-3000 RPM which it appears to be doing. I very rarely rev the engine over 2700 RPM as it is so I will keep an eye on it until it fails again. I still suspect the [aging] vacuum solenoid.

Paul
 
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