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Discussion Starter #21
Marde, I do not believe my car is a PZEV. It was purchased new in New York state even though it is now in Wisconsin. I searched the web to see how to tell a 2010 PZEV from a non-PZEV and could not find any easy way to tell the difference. Earlier years were easier to tell. My VIN is 1FAHP3HN6AW160064 if that tells you anything. I will email you some engine pics. Thanks, Mike
 

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This situation is kinda pissing-me-off. I hate the unknown, or missing links, or missing info and my ignorance. I'm stumbling because of these factors.

The biggest thorn in my ass at the moment is:
What is the difference in-between a 2010 PZEV verses non PZEV? I am very aware of what Ford Focus PZEV is, and what "PZEV unique" car equipment is ((i.e., steel-aluminium fuel tank, PZEV EVAP system, SAI (secondary air injection) system, 3-catalytic converters)) but I am struggling with this situation, verses the diagram that Paul provided, verses your test results.

Side Note: My 2004 wire diagrams show PZEV unique wiring WHILE ALSO showing the non-PZEV wiring. The problem with the 2010 diagram we are using is that is does not show the differences, it only shows the PZEV config.

Among many of my thoughts; one guess is there might be one or more pin-number typos in the wire diagram. This typo shit happens, rare, but it does happen. << happens in Aviation too >>.

...
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...
That test result makes little or no sense. It might make more sense IF you were testing the wrong wire due to a typo in the wiring diagram. Maybe-maybe pin-2 is the PCM input as opposed to the Vref signal. No way to figure this/that out without (1) an accurate wire diagram for your car or (2) lots of ohms tests of each wire to figure out what-wire-is-what.

...My VIN is 1FAHP3HN6AW160064 if that tells you anything...
Ford VIN Etis website is failing me atm. They say (1) website VIN info is offline and (2) your car is a 2004 and the car color is Sangria Red. wtf?

I got your emailed pics. Thanks. Yes, I can not see the tail-tale signs of PZEV components in your engine like I can in the older (2003-2007) engines. IIRC NY was/is a State that delivers PZEV cars to the dealerships. I will assume your car is a PZEV until other info follows.

I need a beer. Oh, wait, I have one. I need a pill.
 

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So, after my pissing, moaning, rant...

Disconnect the car battery first.

Could you please Ohms test the wire from IMRC Module pin-2 to the PCM C175E pin-63. This will confirm this particular bit of info in the wire diagram we are using. This test result should be a normal short (less than 1 ohm). Perform this test while both sides are disconnected. Pin-63 should also wire-connect to MAP sensor pin-2. If you do not find a normal short, try the other pin, pin-3 to pin-63.

C175 are the three(3) PCM connectors; mine are C175B, C175E, C175T. Your PCM is located next to your car battery. I see your PCM in the pics you sent me. Your C175 connectors might be sealed with aftermarket sealant, it looks strange. That connector sealant might be prior handy-work, or maybe just normal... I'm not sure because of lack of picture detail, picture sharpness. It does look strange though.

Side Note: my 2004 PCM is not located in the engine bay like yours.

Which C175 is B or E or T? I do not know. You gotta figure that out.


Here is a PCM C175B, E, T, picture I found online. Please note the highly likely TYPO in the name of the connectors. The actual C175E is the larger (70-pin) one BUT the pic shows it named C175T.
 

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Discussion Starter #24
Thanks Marde,

1. Originally Posted by [email protected] View Post
...
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...

Sorry Marde but I had a typo in the above statement. It was Module pin "3" that varied from 0.7v to 0.1v when manually moving the flaps from open to closed NOT pin 2 like I said. Again sorry.

Regarding the wire resistance from pin #63 at the PCM plug to pin#2 at the Module I did in fact get 0.0ohms indicating that the wire is the same one and does not show high resistance. Also measured 0.0ohms to pin #2 at the MAP sensor.

I do have a metal fuel tank but I think all 2010's both PZEV and non-PZEV's do. I do not see any provision for air injection to the exhaust manifold and my air cleaner is easily serviceable to replace the element.

What now?

Thanks, Mike
 

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I only have a couple minutes to chat, but I should return later today, in 4 hours or more.

There are still a few un-answered questions, but I am feeling a little better that the 2010 wire diagram matches your car config. Car is or is not PZEV does not matter too much atm.

Side Note: I helped a guy with a Ford Ranger Duratec engine inside a custom car about 3 years ago. During this, I learned that Vref can be 12V or 5v based on Year and/or Sensor/System. I have only seen these two Vref voltages in automotive use. My automotive experiences are very limited, and largely with this 2004 Focus.

Your car PCM "seems to have" Vref at .7 to .8 Volts for these 2 systems/parts. I initially dismissed this as bad info, or an invalid test. We must consider this Vref normal until we can get additional info to confirm this is abnormal.

Please review your initial test results: Did test 2A and 2C have the MAP Sensor electrical connector disconnected? Do you remember? Side Note - test 2B was skipped or deleted, is not in spreadsheet.
 

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Discussion Starter #26 (Edited)
Please review your initial test results: Did test 2A and 2C have the MAP Sensor electrical connector disconnected? Do you remember? Side Note - test 2B was skipped or deleted, is not in spreadsheet.

Yes tests 2A and 2C did have the MAP sensor electrical connector disconnected.

Test 2B was skipped because engine running or off with key on made no difference between tests 1A and 1B.

In other news: I thought the 0.7v Vref was low and should be 5 volts from online things I read so I replaced the PCM with a good used one I had but did not get it programmed at the dealer to run the car figuring it might still power the IMRC Module circuit and it did but I still measure only 0.7v to the #2 module terminal. This would seem to rule out the PCM as being bad??
 

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...Yes tests 2A and 2C did have the MAP sensor electrical connector disconnected...
The question and answer is not too important, but it is only right that I explain why I asked: I previously noticed the Module (pin-1) PCM Input "floated high" (3.8V) while disconnected, and I wanted to confirm this was also the case in test 2A & 2C (then yesterday noticed you did not say if the MAP sensor was or was not connected) this made me curious. PCM MAP input floats at 5V is a bit different than the IMRC Module, but is not a big deal to me atm.

I wonder if this is a clue? That PCM input floating at 5V while at the same time we are looking for and expecting the Vref to be 5V, -interesting to note.


...
In other news: I thought the 0.7v Vref was low and should be 5 volts from online things I read so I replaced the PCM with a good used one I had but did not get it programmed at the dealer to run the car figuring it might still power the IMRC Module circuit and it did but I still measure only 0.7v to the #2 module terminal. This would seem to rule out the PCM as being bad??
That is a fair assumption. You could also say the reverse, that both PCM's are good. Hmmm?

So, we are at a fork in the road.

Road-1: The PCM Vref output, at .7V might be normal. We need another car (or Ford technical data) to confirm this. At this moment I prefer Road-2.

Road-2: This might sound funny or hard to believe, but I promise you this does occur. I have seen it in Aviation at least 5 times. I call this a Load Induced Open Circuit (LIOC). A LIOC is where a circuit Ohms tests OK, but when you turn the circuit On, the circuit fails. It is the voltage & current flowing thru the circuit that exposes a fault. This fault can result in an Open or it can result in a Resistance, -very similar to a physical resistor.

Now let's consider this LIOC to your situation. The key item in your situation is splice S123. To confirm the S123 LIOC possibility, you will have to perform the following test.

Disconnect C175E and back-probe pin-63 with a needle (I saw you using a safety pin in one of your pictures). Before re-connecting C175E, use your meter to ohms test the back-probe needle is fully seated and is electrically connected to pin-63. Now re-connect C175E to the PCM. Connect any and all other connectors.

Power-up the car (Key On) and test the voltage output of pin-63 using your back-probed needle (positive) and use (1st test) the car battery as ground reference and (2nd test) use any one of the other ground references we discussed previously; I think you were using the CHT Sensor pin-2.

This test will confirm the PCM Vref output AND confirms the possibility of a LIOC at splice S123.

Gd Luck
 

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Discussion Starter #28
Looks like Forum members are out of ideas.

I scheduled a visit to the local Ford dealer for Thursday to do a $160 Diagnostics Check on it. Hope they can tell me what is causing my P0642 CEL.

Hoping I can still fix it in the two remaining days till then.
 

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Discussion Starter #30
Marde,

Just read #27 and performed the two tests you recommended.

I Got 0.7v with terminal #63 grounded through the voltmeter to the battery and the same 0.7v grounded to the CHT pin #2.

I am about out of ideas. I have plenty of time the next two days to try more suggestions if you have any. I'm not working right now.

Thanks, Mike
 

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Bummer, I was hoping you would find the fault with that test.

Guess Road-1 is back in play.

I gotta go, -drama with my daughter. I will put my thinking cap back-on, and post back tmr after work.
 

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Discussion Starter #32
Marde,

I think I found the problem! Paul suggested that a bad sensor was draining the voltage from the PCM that was trying to put out 5v but couldn't due to a sensor short of some kind and that I should monitor Vref voltage while disconnecting all Vref sensors. I did this and after 7 or so sensors got to the power steering pressure switch near the pump. When I unplugged this sensor Vref jumped from 0.7v to 5.2V!!! I am on my way to Autozone to get a new pressure switch/sensor.

I will confirm here that the problem is fixed or not tomorrow when I know for sure.

Many thanks for your's and Paul's help. Teamwork paid off I think.

Thanks, Mike
 

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Wow! Fantastic news!

I just saw those other old threads you un-earthed today. During this journey, I forgot to search for similar-subject threads. Whoops. I really had my blinders on, especially by only looking at the single page wire diagram we were using. Big lesson learned.

Very very glad that Paul got re-engaged.

One person (from 2014) even spelled it out, nearly spoon fed the problem to us.

The information I found for P0642 - Sensor Reference Voltage 'A' Circuit Low

Possible causes:
- Faulty Engine Control Module (ECM)
- ECM harness is open or shorted
- ECM circuit poor electrical connection
- Shorted sensor on 5 volt circuit
Congrats on the find & the fix.
Cheers!
 

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Marde,

I think I found the problem! Paul suggested that a bad sensor was draining the voltage from the PCM that was trying to put out 5v but couldn't due to a sensor short of some kind and that I should monitor Vref voltage while disconnecting all Vref sensors. I did this and after 7 or so sensors got to the power steering pressure switch near the pump. When I unplugged this sensor Vref jumped from 0.7v to 5.2V!!! I am on my way to Autozone to get a new pressure switch/sensor.

I will confirm here that the problem is fixed or not tomorrow when I know for sure.

Many thanks for your's and Paul's help. Teamwork paid off I think.

Thanks, Mike
[:)]

Paul
 

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Discussion Starter #35
Well the good news is the car now runs great and the CEL stays off. I think it will pass emissions now.

The bad news is the IMRC still is not acting quite right. On initial engine start the flaps cycle from open to closed to back to open, stay there for a few seconds then close again and stay there as the engine idles. All this seems right. However after I drive someplace and without turning the engine off, open the hood and check the flap position they are open and I believe they should be closed at idle. At this time if I ground the vacuum solenoid the flaps close and will stay closed as long as i keep the manual grounding. Seems like I still have an issue but it doesn't seen to trigger the CEL. Can probably drive it this way for another year and it will have 255,000 on it by then so probably ready for the junk yard anyhow. Thanks for all the help forum contributors. Mike
 

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