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So the issue here how a potentiometer functions. Power into the sensor (VREF), Ground (RTN) & output from the sensor to the PCM.

As the sweeper moves with the throttle shaft it varies the output to match the throttle blades position.

The two internal sensors share a single VREF & SIGRTN source. It this were bad other codes would generated.

TP1 (NEGATIVE SLOPE) should show VREF +/- at rest back to the PCM

TP2 (POSITIVE SLOPE) should should less than 1VDC at rest back to the PCM

That how these sensors function.
The reason why you don't test against your 12 VDC terminal Positive or Negative) is because unlike other circuits in the PCM the electronic throttle control is handled by a microprocessor. Other various systems use a clean ground that helps to filter out various electrical noise.

If the Sensor is seeing voltage on the VREF & Output then it will show a circuit high and trigger a CEL.
 

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2017 Kona Blue ST1
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LOL you assholes got me busting out the visual aids.

Good working TB (stock 2.0)
Bench power supply set to 5 VDC for VREF & -5 VDC to simulate PCM processor output.

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Highlighting what @SSgtjrobertson says in an earlier post "unlike other circuits in the PCM, the electronic throttle control is handled by a microprocessor." This means ETC sensor circuitry is pretty sensitive / high performance stuff, isolated from the rest of the electrical system. There should be some really good isolation to supply really clean Ref and Rtn ... AND ... super fast sampling AD converters to read those TPs analog voltages ... and compare the results with the expected angle of the Throttle plate. Just saying those TP sensor inputs might be a little bit more "sensitive" than other PCM circuits.

My assumption is that the PCM is faulty ... putting out reference voltage on Pin 81. It would be nice to see that on a scope. It would also be nice to see what a "good" PCM TP2 signal trace looked like.

Could you try an oscilloscope on TP2 sensor line when it is hooked up to the TB to observe the signal?

It seems it would clearly show the level of the signal over time ... validating my assertion is that the original PCM failed - not sure how - pin 81 to ground doesn't seem like that would cause a failure ... perhaps pin 81 to system voltage (12V) rather than vRef of 5V could have cause it. The replacement PCM might have been subject to the same failure when it was swapped in, causing it to also fail in the same manner as the original PCM ... I don't know.

Now that the wiring is cleaned, tested and TB has been thoroughly tested ... I think the PCM needs replaced.
 

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2013 ST2, AGP BWS turbo, long block
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So the issue here how a potentiometer functions. Power into the sensor (VREF), Ground (RTN) & output from the sensor to the PCM.

As the sweeper moves with the throttle shaft it varies the output to match the throttle blades position.

The two internal sensors share a single VREF & SIGRTN source. It this were bad other codes would generated.

TP1 (NEGATIVE SLOPE) should show VREF +/- at rest back to the PCM

TP2 (POSITIVE SLOPE) should should less than 1VDC at rest back to the PCM

That how these sensors function.
The reason why you don't test against your 12 VDC terminal Positive or Negative) is because unlike other circuits in the PCM the electronic throttle control is handled by a microprocessor. Other various systems use a clean ground that helps to filter out various electrical noise.

If the Sensor is seeing voltage on the VREF & Output then it will show a circuit high and trigger a CEL.
I am familiar with potentiometers.. but that test table is pretty sweet.

Your testing inspired me to test all 3 of mine. As you noticed, the results I was getting back from the new 2.3L TB in the car were bad.
I used an iPhone charger brick to usb with the power wires stripped back as 5v source (test verified).
I used a 9v battery as TACM+ / TACM- (tested at 8.79v and 1.5amp briefly). I verified polarity with each test.
  1. New 2.3L Throttle Body
    1. TPS1 busted - steady 1.1v
    2. TPS2 busted - about 0.0v with odd 0.001 blips during operation.
    3. TACM+/- blade very snappy response to full open.
  2. 2009 duratec 2.5L Throttle Body on hand
    1. TPS1 values within appropriate range but do not perfectly pass each other
    2. TPS2 values within appropriate range but do not perfectly pass each other
    3. TACM+/- blade sluggish but eventually opened full.
  3. old 2.3L Throttle body in the car during break down
    1. TPS1 values within appropriate range but do not perfectly pass each other
    2. TPS2 values within appropriate range but do not perfectly pass each other
    3. TACM+/- blade hardly moves -just suck battery
I also threw the 2012 PCM on hand back in the car for verification am still seeing 4.8v coming back out of TP2 PCM input wire just like 2.0L stock PCM.

* important. I did put the old 2.3L TB in the car with this 2012 PCM in at one point. Was trying every combination on hand to see if any of them worked.
**** important. The new 2.3L has had the longest exposure to the 4.8v coming back at its TPS sensor. Likely why it no long works at all


So what this leaves me thinking is the old 2.3L TB scraps every PCM it connects to. But its odd that the TP1 and TP2 sensors work fine for it. It seems like the H bridge getting fried by the old 2.3L throttle body has some effect on the eTPPC.
 

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2013 ST2, AGP BWS turbo, long block
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Any advice on buying the right PCM? I messed that up last time.
Good thing too. the 2012 one was only $40
 

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2013 ST2, AGP BWS turbo, long block
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Yeah but thats for an escape. it has the same hardware number but a different part number

my 2013 focus ST:
P/N: CM5A-12A650-APH
H/W: BB5A-12B684-AC

will that work with a different P/N? $160 is way cheaper than what I'm seeing for P/N match
 

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I found this, no need to reprogram if you send the original.
 

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2013 ST2, AGP BWS turbo, long block
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Oh wow my P/N actually shows up as a 2014 PCM. great. One of the previous dealers must've stuffed a 2014 PCM in to my 2013.
 

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2017 Kona Blue ST1
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I'm working on hot wiring this Damaged PCM for my other project. Which I'm behind on, because I've been here LOL!!!🤣

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The test board I built is to teach automotive electrical theory and to help with another future project (video series)
 

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I found this, no need to reprogram if you send the original.
PATS will need to match. Can't remember if Forscan can do PATS or not...
 

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Yeah but thats for an escape. it has the same hardware number but a different part number

my 2013 focus ST:
P/N: CM5A-12A650-APH
H/W: BB5A-12B684-AC

will that work with a different P/N? $160 is way cheaper than what I'm seeing for P/N match
from parts.ford.com i looked up the
Eec V Engine Control Module
using my vin for my 2013 ST

the ford website states it also
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Forscan can do PATS. mine just won't. Thinking my adapter is busted.
you sure it can do PATs for the ST its been a few years since i looked into it but it still didn't support the MK3 yet.
 

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2013 ST2, AGP BWS turbo, long block
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Okay so I just got a working throttle body
and a BRAND NEW PCM for the appropriate year and model.

Still seeing 4.8 volts coming back from the PCM on the TP2 wire.
looks like I'm not driving this hunk of **** any time soon
 

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So you replaced the PCM. What TB did you use?
 

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2013 ST2, AGP BWS turbo, long block
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I didn't plug the only good throttle body in yet. Because whatever is going on from the PCM is wrong. And I don't want to scrap another TB

The throttle body is tested good as per posts further up in this thread.
 
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