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P0190 indicates the reference voltage (Vref) from the PCM to the FRPS is not between 4 to 6 V as it should be. This could be a wiring problem (a broken wire between the PCM and FRPS), a bad FRPS, or a bad PCM. The FRPS, Throttle Position Sensor (TPS) and Differential Feedback Pressure EGR (DPFE) sensor share the same PCM Vref--if either of them were defective it could cause P0190.

So:

  • Check the voltage between the brown/white wire at the FRPS and ground, key on engine off (KOEO). It should be 4 to 6 V with around 5 V being "normal";

  • If it is not in that range unplug the TPS and check again at the FRPS, if the reference voltage is now present the TPS may be shorted internally);

  • If there is still no reference voltage at the FRPS unplug the DFPE sensor and check again at the FRPS, if the reference voltage is now present the DFPE sensor may be shorted internally);
If unplugging the TPS and DFPE sensor does not restore Vref on the brown/white wire at the FRPS then the wiring harness is open someplace between the PCM and the FRPS, or the PCMs internal Vref supply is bad.
 
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What is DFPE and VREF? TPS is throttle position sensor right?
P0190 indicates the reference voltage (Vref) from the PCM to the FRPS is not between 4 to 6 V as it should be. This could be a wiring problem (a broken wire between the PCM and FRPS), a bad FRPS, or a bad PCM. The FRPS, Throttle Position Sensor (TPS) and Differential Feedback Pressure EGR (DPFE) sensor share the same PCM Vref--if either of them were defective it could cause P0190.
 

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Discussion Starter #6
Mathew r Wright said:
So can a bad EGR cause this?
Ok sorry cliff I'm dumb I actually read what you said so yah that makes Sense. I don't have a volt meter though. Oh yah and where is the DFPE located?
 

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Mathew r Wright said:
Ok sorry cliff I'm dumb I actually read what you said so yah that makes Sense. I don't have a volt meter though. Oh yah and where is the DFPE located?
By the firewall driver side

ForumRunner_20121122_135320.png
 

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Discussion Starter #12
mymustang said:
If you have to replace that part,,it wont look like that,,they have replaced it with a plastic black one
Ok we'll at least I got an idea what it looks like and location thanks for your guys help
 

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Discussion Starter #13
Ok so I'm getting normal current to my FRPS, so im wanting to if the FRPS can be ohmed for resistance or will I not be able to tell its bad.
 

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Discussion Starter #14
Here's some signs and symptoms my car is giving me. When I put gas in Monday notice my fuel gauge took a min or two to reach the actual reading. Meaning the needle on the gauge slowly climbed up to three quarter a tank, it's has been consuming gas real bad, stalled one day, service engine light came on, now there is a real bad miss like act to her, no power, and fuel pressure fluctuates a lot with key in the key on position? So let me ask what you guys think? I'm starting to think its the fuel pump???
 

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Ok so I'm getting normal current to my FRPS, so im wanting to if the FRPS can be ohmed for resistance or will I not be able to tell its bad.
I believe you mean you measured the voltage, not the current (amperage). No offense meant, it's just that after 45+ years of engineering I can't help it. Also one does not "ohm" a device any more that one would "volt" it or "ampere" it--it's just called measuring its resistance, the unit of measure is Ohms.

The FRPS sensor element is a piezo-electric strain gauge, measuring its resistance would not produce any meaningful vale (I.e measuring its resistance would be futile :) )

You can however measure its output voltage and compare it and the fuel pressure reading to the chart below:



With the engine idling the voltage between the red/pink and gray/red wires should be reasonably steady, and around 2.2 to 2.4V (fuel pressure at the rail of 30-32 psi, the OBD2 PID should be 40 psi or so). If it is not then the FRPS is likely bad. If the voltage is as indicated then the problem could be in either the Fuel Pump Driver Module, or the pump itself.

Testing the fuel pump driver module is rather involved, and requires Ford's IDS (Integrated Diagnostic System) to be done easily. Here is the wiring diagram for the fuel pump, which may be of some assistance.

 

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Similar problems here. Could really use your help cliff.

FRPS voltage readings:
Key on engine off

BN/WH 4.99V
GY/RD .01V
RD/PNK 2.13

Key on engine @idle:

BN/WH 5.04-5.14v
GY/RD .06-.16v
RD/PNK 2.84-2.88V

Tried replacing the FRPS, no change, what do I test next and what does it rule out, etc, etc?
 

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Cliffy's posts are probably going to be the most help that you will find on this website, at the present time.

Have you done a fuel pressure test?
 

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I figured.

I already sent him a pm letting him know about this post and also telling him the same things on the list post. Just waiting g for him to have time to reply.
 

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Not sure if he will reply or not. He has only been coming on this forum infrequently lately, and I don't know that there is anything more that he can add, than is already posted here.
 
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