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Discussion Starter #1
Does anybody know how to test the three terminal 8S4Z-9P471-A tumbler rotary position sensor used on a 2010 Focus 2.0L?

My CEL came on with codes P0642 and P2004. I changed this sensor with a new one as well as the vacuum solenoid and checked the vacuum lines and verified that the vacuum actuator works with an external vacuum source and there is no mechanical binding or vacuum leaks. I am ready to replace my ECU as it seems it is not sending voltage to the vacuum solenoid to activate the tumblers from their no-vacuum position but thought I may have gotten a bad replacement 8S4Z-9P471-A rotary position switch and wanted to check it first.

The vacuum actuator is in the UP position when I start the vehicle and it never moves regardless of engine rpm. It moves easily when vacuum is applied either from the car or externally.

What can cause the solenoid to not get a 12v signal from the ECU on engine start up besides a bad ECU?

Thanks, Mike
 

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I have zero knowledge of that system on the 2010, but I am very familiar with the same system/s in the 2004 2.3 engine and thru 2007 2.0 Duratec engine.

Your part descriptions and vac testing has me a bit confused. I will not ask you to help me learn about the 2010 version of this system.

Adding to what AMC49 said:
If like the older cars (2004-2007) the IMRC Solenoid/s are always powered (12Vdc) and are controlled by a "controlled ground" via the PCM/ECM.

I want to caution you; please do not replace the PCM/ECU until after you have performed some "end-to-end" wiring checks (and some misc other checks) by using a meter and the 2010 wiring diagrams.

My first guess is that you have a vac hose leak DESPITE the external vac test equipment that you used. Did your vacuum test include all the vac hoses in this system? I know (first hand) that some vac leaks can be hidden from the naked eye. Some vac hose damage is only seen once the hose is removed from the car; to release & relieve the hose of its' typical old positioning while installed in the car.

Gd Luck
 

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Discussion Starter #4
Vacuum is good, solenoid is good ad tumblers are not sticking. When I ground neg wire going to the vacuum solenoid the tumblers close and stay closed as long as I keep the ground.

So my problem has to be upstream from the vacuum solenoid which as far as I know is just the wire harness to the PCM and the PCM itself.

Any other ideas?
 

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Vacuum is good, solenoid is good ad tumblers are not sticking. When I ground neg wire going to the vacuum solenoid the tumblers close and stay closed as long as I keep the ground.

So my problem has to be upstream from the vacuum solenoid which as far as I know is just the wire harness to the PCM and the PCM itself.

Any other ideas?
Based on my clear understanding of the same-similar system in older cars (2004-2007) your testing and descriptions make complete sense, and I agree with you.

The fault should lie within (that wire) the wiring from the IMRC solenoid to the PCM, -or the PCM is defective. You should refer to the 2010 wiring diagrams and ring-out (test) the associated wiring.

If anyone here has the needed 2010 wiring diagram PLEASE help him out. For 2004, the IMRC wiring info is inside diagram #26 "Engine Controls".

Most car repair shops have access to the "pin-out" information that you need. Stop by a local garage and ask nicely, they might give you the needed pin-out info for free.

If the wiring tests pass, I would still caution you from replacing the PCM without addition thought and testing. My light suspicion is a different problem: the IMRC Actuator and associated wiring. The PCM will not engage ((ground)) the IMRC Solenoid if the Actuator does not have communication to the PCM. So, the PCM effectively "watches" the Actuator to see if the actuator is working properly, and only then does the PCM allow the solenoid to engage. The exception to this rule is at first key-on, engine-on. So, it should work on first power-up, but after that, if something is wrong, it will get stuck in a failed state.

Once the IMRC system has failed, ((aka -the PCM fails the continuous IMRC Actuator self-check)) the PCM will not allow the IMRC system to work again (will not ground that solenoid) UNTIL you turn the engine and key off.

Sorry if I am rambling-on,... I am unsure about the 2010 wiring, and also do not know the PCM (firmware) operational characteristics of the IMRC system for the 2010.

Gd Luck
 

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Discussion Starter #6
Based on my clear understanding of the same-similar system in older cars (2004-2007) your testing and descriptions make complete sense, and I agree with you.

The fault should lie within (that wire) the wiring from the IMRC solenoid to the PCM, -or the PCM is defective. You should refer to the 2010 wiring diagrams and ring-out (test) the associated wiring.

If anyone here has the needed 2010 wiring diagram PLEASE help him out. For 2004, the IMRC wiring info is inside diagram #26 "Engine Controls".

Most car repair shops have access to the "pin-out" information that you need. Stop by a local garage and ask nicely, they might give you the needed pin-out info for free.

If the wiring tests pass, I would still caution you from replacing the PCM without addition thought and testing. My light suspicion is a different problem: the IMRC Actuator and associated wiring. The PCM will not engage ((ground)) the IMRC Solenoid if the Actuator does not have communication to the PCM. So, the PCM effectively "watches" the Actuator to see if the actuator is working properly, and only then does the PCM allow the solenoid to engage. The exception to this rule is at first key-on, engine-on. So, it should work on first power-up, but after that, if something is wrong, it will get stuck in a failed state.

Once the IMRC system has failed, ((aka -the PCM fails the continuous IMRC Actuator self-check)) the PCM will not allow the IMRC system to work again (will not ground that solenoid) UNTIL you turn the engine and key off.

Sorry if I am rambling-on,... I am unsure about the 2010 wiring, and also do not know the PCM (firmware) operational characteristics of the IMRC system for the 2010.

Gd Luck
Many thanks for your informative reply. It helped me a lot. I forgot about the system check at start up and was not fast enough to start the car and get under the hood to observe the actuator cycling at start up so my wife started the car and I observed the actuator cycling like it should but then returning incorrectly to the open position shortly afterward. This tells me the wiring between ECU and the solenoid is not the problem.

One difference between your generation Focus and mine is the sensor for the tumble flap position is separate from the actuator on the 2010 Focus. In fact while there is still an electrical connector on the vacuum actuator, there is no plug on the harness for it. Instead there is a specific sensor for the tumble flap position. This is the sensor I replaced first with a brand new Ford one but am even more convinced that my brand new sensor is defective causing the ECU to not get a logical reading for the tumble flap position and shutting this function down to the default, open position. Will get another new Ford sensor Monday and hope this fixes it. Again, thanks for your detailed reply.
 

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The OPs thread title is very confusing. I assume his 'tumbler' = IMRC

BTW just because the IMRC is not responding (moving) does not necessarily mean the problem is either the IMRC module or PCM. If the PCM does not get a specific input from other sensors it may have a default strategy of turning off the solenoid. Need to know the code setting criteria/failure management strategy.

If anyone here has the needed 2010 wiring diagram PLEASE help him out.
Attached

Good luck
Paul
 

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Discussion Starter #8
Many thanks!! Yes, what I call tumblers you call IMRC. I called them tumblers to differentiate from the earlier generation Foci that had both tumblers and IMR flaps. Mine just has the on/off vacuum triggered tumblers. My IMRC actuator does not have any wires going to it, just a vacuum hose from the IMRC solenoid. I do have a a tumble flap position sensor that has wires going to it to tell the ECU what position the flaps are in. I replaced this position sensor once already with no change in operation. On your wiring diagram it shows the IMRC and this flap position sensor in the same unit which it was on earlier cars. Anyway I agree with you that it could be a sensor telling the ECU not to send ground to the solenoid. I just don't know what other sensor it could be other than the flap position sensor. That is why I was looking for a way to test this sensor with a multimeter in my original post but nobody seems to know how to do this including Google. So I ordered yet another new flap position sensor to try for $83 more. It will be here Tuesday. Do you have any idea what other sensors the ECU might be looking at to determine if it should trigger the IMRC solenoid? Again, many thanks. Mike

Images of 8S4Z-9P471-A Flap Position Sensor at:

https://www.google.com/search?q=8S4Z-9P471-A&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjZl7mLxdjhAhUyJTQIHb81CvIQ_AUIDygC&biw=1152&bih=562#imgrc=H0mAF6Hsu-aEVM:[/URL]
 

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Many thanks!! Yes, what I call tumblers you call IMRC. I called them tumblers to differentiate from the earlier generation Foci that had both tumblers and IMR flaps....
No, Paul and others (and me) are not calling the tumblers->IMRC. We say IMRC to ID the entire system, and not to ID any single component of the system.

All the older Foci with Duratec (to include your 2010) have only IMRC, with the unique exception of the 2003-2004 2.3 Engine, which has a second sister system, IMRC and IMTV.

Here is my recap of part names for the IMRC system.

IMRC Solenoid
IMRC Actuator - I guess this part dropped the electrical interface in 2008.
IMRC Module - aka flap position sensor. I guess this part first appeared in 2008.
IMRC Flaps - aka tumble flaps, aka swirl flaps, aka runners.

Side note: There is a much different IMRC Module mixed in some of the older (2000-2003) Zetec engine cars. I am not addressing that Module in this thread. That old IMRC module was a box that was sometimes opened-up by DIY'er for mechanical clock-work repairs.


...Anyway I agree with you that it could be a sensor telling the ECU not to send ground to the solenoid. I just don't know what other sensor it could be other than the flap position sensor...

Do you have any idea what other sensors the ECU might be looking at to determine if it should trigger the IMRC solenoid?
I realize that your questions are directed at Paul, however, this is a team sport, so I will also reply.

My first and most important answer to your question is "I do not know". My knowledge of this system is limited, is a collection of reading threads here, and some hands-on repair efforts too.

I can't tell you what sensors the PCM depends on for proper operation of the IMRC system, or what sensors might cause the PCM to disable the IMRC.

The (my) basic understanding is this: the PCM moves the IMRC flaps based on throttle position and/or speed and/or engine RPM and maybe MAP and MAF info too. At somewhere around 2500-3000 rpm the flaps move from the normal (low RPM) position Closed to Open. The flaps live 95% of there life in the Closed position while the engine is on. The flaps live 99% of there life in the Open position while the engine is off.

Please note these two exceptions or questions:

#1 - When driving fast down a freeway (70-75 mph or 2500-2800 RPM) I am unsure if the flaps are Open or Closed. It is my belief and guess that the flaps are Closed while cruising down the freeway. BTW I have no Tach, so I am unsure about speed verses RPM.

#2 - There are verified stories here at FF that some cars IMRC hold or "trap" vacuum pressure when the engine is turned off. In these cases, the IMRC flaps are held in the Closed position, despite the engine Off.

Lastly, Paul made a good point and a very good question. What DTC (codes) does your car have?
 

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Discussion Starter #10 (Edited)
Many thanks for the additional info. My 2 codes are P0642 sensor reference voltage “A” circuit is too low and P2004 intake manifold runner stuck open.

Can you tell me if on a 2010 Focus if the Flaps are Open or Closed when there is no vacuum in the actuator and the little white ball joint is up and easily visible while looking at the top of the engine? I assume that this is the Open position?

Thanks again, Mike
 

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Many thanks for the additional info. My 2 codes are P0642 sensor reference voltage “A” circuit is too low and P2004 intake manifold runner stuck open.
P2004 is the normal, to be expected code when IMRC is messed-up. P0642 is odd. That code makes me suspect the 12Vdc voltage reference to the module, or the module itself, or the return voltage to the PCM.

Oh, I just noticed the 2010 has Vref provided by the PCM, so this may very well be a 5Vdc signal as opposed to the more common external Vref 12Vdc. I noticed this after reviewing the diagram provided by Paul.

Please note that the IMRC Module (5Vdc) Vref is shared with the MAP sensor. So if you check this signal (with a meter) please consider checking at both of these locations. Do you have a meter, and are you experienced enough to perform this test?


...Can you tell me if on a 2010 Focus if the Flaps are Open or Closed when there is no vacuum in the actuator and the little white ball joint is up and easily visible while looking at the top of the engine? I assume that this is the Open position?

Thanks again, Mike
Correct, that is the Open position.
 

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Discussion Starter #12
Thanks for the additional info. I am not sure what you re referring to when you say "the module"

I did have a diagnostics code for a MAP sensor a couple of weeks ago but when I replaced the MAP sensor it went away.

I do have a meter and know how to use it but am not sure which terminal to check voltage across and what the readings should be and under what conditions.

Once again what is "the module" you refer to please??

Thanks, Mike
 

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The module = the position sensor. I mentioned this back at post-9. There is no "position sensor" in the wire diagram, but there is a "module".

As for other info, that will have to wait, I'm busy atm.
 

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...
I did have a diagnostics code for a MAP sensor a couple of weeks ago but when I replaced the MAP sensor it went away...
That is a big red flag for me. It is very rare, very strange that the MAP sensor failed. ESPECIALLY NOW, and because you have the "shared Vref" for the module and the MAP sensor and because the IMRC Module is failing AFTER ALREADY having replaced this Module once before. This is way too coincidental.

There is (very likely) something wrong with the wiring for Vref or the PCM is failing. Probably the wiring.

General note about Vref: The reason the PCM uses a Vref signal is due to the sensitivity of these sensors input/output "as detected by the PCM". The Vref output is highly regulated, highly accurate, to ensure the accuracy of the resulting outputs of these sensors.

Use the diagram that Paul posted, and find the PCM output of Vref at C175E Pin#63. Now visually follow this GN/VT (Green with a Violet stripe) wire to the Splice S123. You do not need to find this splice on the car (yet) but I wanted to make you aware of it, because the splice could be faulty. The splice is likely located in the harness between the Module and the MAP sensor.

... I do have a meter and know how to use it but am not sure which terminal to check voltage across and what the readings should be and under what conditions.
The test condition is: Engine On or Off as long as the ignition key is On. Test with engine On if it is not a problem.

Before digging into the bad-splice possibilities, first, test Vref at the connector contact points at the Module and at the MAP sensor. See wire diagram for details. Each of these end-points has the same wire color GN/VT.

Place the Black negative lead of your meter to the car battery negative terminal. Now check for Vref at the Module connector (pin-2), and again at the MAP sensor (pin-2). You can perform this test with the connectors (Module & MAP Sensor) connected (back-probed) using a sewing needle AND also the same test again with these connectors disconnected. Uh, not in that order... use the "connectors disconnected" method first, it is much easier. Then the "back-probe" method if your comfortable or experienced with this.

Vref can be 5Vdc or 12Vdc. I do not know what your car uses for that Vref. I look forward to your test results to learn if it is 5 or 12V. My guess says 5V... even tho my car IMRC Actuator Vref uses 12Vdc IIRC. Different animal.

You will need some small alligator clips, pins, special probes or something similar to use with your meter test leads. Makes life a lot easier. Most-all electricians have this as part of their bag of tricks or are already included with the meter lead set.

Please take great care not to "whoops" short something out, especially since you are testing a Vref supplied by the PCM. The PCM should be designed to LIVE THRU a short of this circuit, but there are no certainties or guaranties. So take your time, and setup the meter red test lead probe/needles/alligator clips carefully BEFORE turning the Ign On.
 

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Discussion Starter #15
Well here is the voltage test data I gathered today. What jumps out at me is the difference in voltages at the IMRC Module connector with the module unplugged (Test 1A) and the module plugged in (Test 1C). I duplicated this with three different modules. Not really sure what this means but perhaps the PCM is not putting out enough current to keep necessary voltage?

See data per the below link:

https://www.facebook.com/photo.php?fbid=10217698419566300&set=gm.751701625224040&type=3&theater&ifg=1[/IMG]
 

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I was primarily interested in voltage only at pin-2 at both locations (module and MAP sensor) while each was connected & disconnected (or a combination of both).

The voltage changes at pin-1 is odd, but is not a concern because that is a PCM sensor "input" which is basically nothing and "floating voltage" and nothing that concerns me (or you) at all.

Your test had all pin-2 measurements at about .7V = not good = invalid test.

So, I have bad news and then some other bad news....

The test results are junk and confusing. I might have wasted your time, and I think I know what I did wrong. The "ground reference" of the meter was placed in the wrong location. Remember I told you to place the black lead on the car battery? Well, that was wrong. Sorry? <blush>.

You will (sadly) need to perform the series of tests again. Place the meter black test lead at either of (any one of) these locations:
Module pin-3
MAP Sensor pin-4
Cylinder Head Temp (CHT) Sensor pin-2
BTW - The CHT Sensor is in the dead center of the engine, on top, between the spark plug coils.

Whoops! Outta time, gotta go, be back later. Here is your test results picture, changed it to a JPEG file format.
 

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I had mistakes-typos on pin-numbers info above, but is now corrected.

Place the meter black test lead at either of (any one of) these locations:
Module pin-3 (is a green/white wire)
MAP Sensor pin-4 (is a green/white wire)
Cylinder Head Temp (CHT) Sensor pin-2 (is a green/white wire)

Sorry about my ground-reference brain-fart mistake. The "free" help info found on the web, posted by Marde, should always be suspect bad info or complete BS.

Gd Luck
 

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Discussion Starter #19
Marde,

Again, many thanks for the help!

I did the following key on, flaps open, voltage tests and IMRC Module pin 2 measured 0.7v on every one. The voltages measured the same with two different IMRC Modules.
MAP plugged in and IMRC plugged in and unplugged
MAP unplugged and IMRC plugged in and unplugged

I did the following key on, flaps open, voltage tests and MAP Sensor pin 2 measured 0.7v on every one.
IMRC Module plugged in and MAP Sensor plugged in and unplugged
IMRC Module unplugged and MAP Sensor plugged in and unplugged

In addition I measured a change in voltage at the IMRC Module pin 2 from 0.7v to 0.1v when manually moving the flaps from open to closed. This was also with key on and both MAP and IMRC Modules plugged in.

What now? New PCM?

Thanks, Mike
 

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Marde,

Again, many thanks for the help!

I did the following key on, flaps open, voltage tests and IMRC Module pin 2 measured 0.7v on every one. The voltages measured the same with two different IMRC Modules.
MAP plugged in and IMRC plugged in and unplugged
MAP unplugged and IMRC plugged in and unplugged

I did the following key on, flaps open, voltage tests and MAP Sensor pin 2 measured 0.7v on every one.
IMRC Module plugged in and MAP Sensor plugged in and unplugged
IMRC Module unplugged and MAP Sensor plugged in and unplugged

In addition I measured a change in voltage at the IMRC Module pin 2 from 0.7v to 0.1v when manually moving the flaps from open to closed. This was also with key on and both MAP and IMRC Modules plugged in.

What now? New PCM?

Thanks, Mike
Hmmmm... I'm not sure what is next. But not a new PCM.

The test results do not match my expectations. I am second guessing the config of your car verses the wire diagram we are using. The pin-out info is "called out" as applicable to PZEV configuration only. So here are my questions:

1- Is your car a PZEV?
2- Is there a second (different) wire diagram showing the same set of systems when the car is non-PZEV?

The wire diagram calls-out this wiring as if "IMRC is only there if car is PZEV"... so this is confusing.

We need to ask Paul if he can dig around for an alternate wire diagram, if one exists.

If you are unsure about your car PZEV or not, send me a couple pictures of your engine to my email, or post them here, attach them here, I can usually tell by looking at an engine.

I have ZERO time left, my Son is waiting for me, we are going to a shooting range. Catch ya later.
 
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