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Matt
Matt, Engineer
Category: Ford
Satisfied Customers: 21982
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Pulling code P2138

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pulling code P2138

Hello

The P2138 trouble code indicates that the Engine Control Module has detected a malfunction within the D and/or E circuits of the throttle position sensor. and there's 2 aspect to check the pedal sensor and the throttle position sensor

The pedal position sensor is located on the gas pedal. There are usually three wires used to determine the pedal position, a 5 volt reference supplied by the PCM/ECM, ground, and sensor signal. A factory wiring diagram will be necessary to determine which wire is used. Make sure the connection is secure and there are no loose wires in the harness.
Check for good ground using a digital volt ohm meter (DVOM) set to the ohms scale by connecting one lead to the ground at the sensor connector and the other to chassis ground - resistance should be very low. Check for 5 volts reference voltage from the PCM by using the DVOM set to volts scale with the positive lead at the wiring harness connector and the negative lead on a known good ground with the key in the run or on position .Check for reference voltage using the DVOM set to volts scale with the red lead on the reference signal and the negative lead on a good known ground with the key in the run / on position - the signal voltage should increase as the throttle pedal is pushed down further.
Typically the voltage ranges between 0.5 volts with the pedal not pressed and 4.5 volts at wide open throttle position. It may be necessary to check the signal voltage at the PCM as well to determine if there is a voltage difference between the sensor and what the PCM is reading. The position sensor signal should also be checked with a graphing multimeter or oscilloscope to determine if the voltage increases smoothly with no dropouts throughout the entire range of motion. If an advanced scan tool is available, the positions sensor is usually displayed as a percentage of desired throttle input, make sure the desired value is similar to the actual pedal position.

Throttle position sensor - The throttle position sensor monitors the actual position of the throttle body blade. The throttle position sensor is located on the throttle body. There are usually three wires used to determine the pedal position, a 5 volt reference supplied by the PCM/ECM, ground, and sensor signal. A factory wiring diagram will be necessary to determine which wire is used. Make sure the connection is secure and there are no loose wires in the harness. Check for good ground using a digital volt ohm meter (DVOM) set to the ohms scale by connecting one lead to the ground at the sensor connector and the other to chassis ground - resistance should be very low. Check for 5 volts reference voltage from the PCM by using the DVOM set to volts scale with the positive lead at the wiring harness connector and the negative lead on a known good ground with the key in the run or on position.
Check for reference voltage using the DVOM set to volts scale with the red lead on the reference signal and the negative lead on a good known ground with the key in the run / on position - the signal voltage should increase as the gas pedal is pushed down further. Typically the voltage ranges between 0.5 volts with the pedal not pressed and 4.5 volts at wide open throttle position. It may be necessary to check the signal voltage at the PCM as well to determine if there is a voltage difference between the sensor and what the PCM is reading. The throttle position sensor signal should also be checked with a graphing multimeter or oscilloscope to determine if the voltage increases smoothly with no dropouts throughout the entire range of motion. If an advanced scan tool is available, the positions sensor is usually displayed as a percentage of actual throttle position, make sure the desired position value is similar to the commanded position value.

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Customer: replied 2 months ago.
I just purchase the fuel rail pressure sensor. but I cant find it on top of the engine. do you kjnow where I can find this?

hello

the sensor should screw into the fuel rail that also connects all the injectors?

this image shows the location on the 450 engine which should be the same as the 350 powerstroke

Customer: replied 2 months ago.
I just replaced my rear calipers on the truck. I bled them after and I'm still getting a spongy push on the brakes when I start the car. is there a certain method of doing this?

Hello

you may have air in the rear proportioning valve

this is usually located on the chassis rail about halfway along the truck and adjusts / restricts the rear pressure to prevent the wheels from locking up and the valve may have a bleed valve on it

so check for that

Matt and 4 other Ford Specialists are ready to help you
Customer: replied 2 months ago.
great thanks. do I have to use the same bleeding technique as I do with the calipers?

hello

yes
I favour having a clear hose from the nipple to a jar 1/2 full of old fluid and with the nipple closed your assistant pushes the pedal up and down a few times then holds it down then you crack open the nipple and close it again whilst fluid is still flowing.

Customer: replied 1 month ago.
I can't find this rear proportional valve along the chassis. Any other thoughts where it might be?

OK if its not on the chassis it could be in the engine bay next to the master cylinder

I've attached an image of what it looks like

Customer: replied 1 month ago.
Are you sure this is for the 2011 6.7l one?

Hello

if the truck has no proportioning valve then its all done with the ABS system and its possible that you need to run the ABS pump to move any trapped air inside

the dealer method is to use the diagnostic tool to cycle the ABS during bleeding

however I've had good results buy just taking the car for short drive and stamping on the pedal at low speed to lock the brakes and trigger the ABS
and then re-bleed

Customer: replied 1 month ago.
i believe i had the calipers on the wrong sides. with the bleeders at the bottom. what i can't find anywhere is what type of brake fluid does the 6.7L take? dot3 or dot4?

Hello

definitely use dot 4 on any vehicle with ABS and Dot 5.1 is even better if you can find it