Having EBP issues and I'm not sure where to turn to next.

Here's what I know:

07 6.0, all stock, no tune.
New Motorcraft EBP sensor and new wiring connector plus pigtail installed after EBP code 470. Did not help.

Anytime EBP sensor plug is connected, reading is 4.53 volts. Doesn't change engine running or key on engine off always 4.53 volts. If EBP plug is disconnected always reads 0.00 volts. Both engine running or key on engine off.

Is it possible I got a bad replacement sensor? Would be unusual to have two bad sensors, but not impossible.

I can double check the wiring on the pigtails to make sure I did that correctly. But I think it's done properly to match new to old.

I'm not sure where to look next. Any suggestions?

Does anyone know what the pins on the connector should read? Or what the resistance should be between the pins on the sensor?

Thank you!

 

What psi does the sensor show?

 

The "EBP gouge" reading from Forscan is 268kpa - so that's about 38.8 psi. At idle or engine off key on. As long as it's plugged in.

 

Connector C1271.
On the female connector, with the latch at the top:
Pin 1 on the right
Pin 2 on the left
Pin 3 at the bottom

Pin 1 - Gray with Red stripe wire - Signal return (essentially a ground)
Pin 2 - Brown with White stripe wire - Reference voltage
Pin 3 - Violet with Light Blue stripe wire - Position sense

Sounds like you might have the BN/WH wire swapped with the VT/LB wire, or there is a short in the harness.

According to the manual - 4.8 volts should be about 83 psig. Your pressure reading might be a default.

 

Thank you! That is super helpful! I'll have to take a closer look and see what I find on the wiring side.

Measuring the removed sensor. Based on the assumption that it's a simple two resistor voltage divider circuit and the reference side is a fixed resistor the sensor is variable, it would read around 2 volts on pin 3 when 5V it applied to the pin 2. I'm not sure what it should read as a baseline at normal atmospheric pressure.

The reason I am a little confused on the diagnostic regarding a short in the wire is that I'd expect it to read either zero or 5V when unplugged and plugged in. The high voltage when plugged in tells me that something is off in the sensor. So I assumed new sensor would fix. I did the wiring plug replacement first. Maybe I screwed it up and should have done the sensor first. But based on the resistance between the two pins and the reference voltage pin I still can't see how it gets to a reading of 4.5 volts. I'll have to go do some more measuring of what's going on on the plug end side. I have a few resistors so I can make my own voltage splitter to send a known voltage back to the PCM and see how it reads it.

But first - I'll look at the wire colors to pins. That's probably my most likely spot to find a fix.

 

The manual states about 0.8 volts at 14.7 (atmospheric) psia (0 psig)

 

The sensor if I recall correctly is a integrated circuit and not the simple resistor divider.

 

Did you double check the tube is not clogged up? That appears close to reference voltage.

 

You re-wired the pigtail, might make sure you didn't cross any wires? I purchased the Accurate Diesel EBP pigtail and the wiring colors were of course different than the stock wiring. Various shades of green.

https://www.accuratediesel.com/6-0l-...connector.html

 

Thank you for all of the help. I finally got a chance to work on it today for a bit. Wires were crossed on my replacement pigtail. Here's the worst part - They crossed inside the pigtail housing. Not lying. Visually I had it right, but the wires coming out of the replacement plug I got from Amazon were all 3 the same. And I pulled the plug backside apart and sure enough - inside of the plug pins 1 and 2 crossed over to the opposite sides. So it was wired backwards.

I fixed the wiring and now its good to go. Readings are as they should be off and at idle. I'll take it for a drive later today and make sure it's all squared away.

I shouldn't have swapped sensor and wiring at the same time. And should have bought a better pigtail. It was mostly just what I could get in my hands ASAP to do the swap. Probably didn't need the wiring, but it seemed like a good preventative thing while I was doing the sensor.

 

Good job of hunting. Many would not have thought of checking that, and this is a good reminder for all to check aftermarket pin to wire assignments.

 

Glad you got it taken care of!

 

The OEM pigtail is something like $60-70 so it's hard not to pass up the $10 ones on Amazon. I went with Accurate Diesel as they at least have some credibility on their $10 part.

Glad you got it figured out! Sometimes the new parts are to blame!

 

I took a picture with my phone when I was was working on it. Sorry about the delay - just haven't had time to upload and post it up. You can see what was inside the back end of the plug. I bet some dude in China had a good laugh.

When I went back with the info you guys shared with me everything pointed to the wiring being backwards between pins 1 and 2. My background is physics and mostly telecommunications and electronics, so I'm usually pretty good at diagnosing electrical issues. And the fact that I had just swapped the plugs made it even more likely that I screwed it up myself.

I've been there before in one of the most frustrating projects I've done. I have a CNC plasma/router table that I built about 5-6 years ago and I ordered some cheap chinese stepper motors for it. My setup uses 5 motors. I could not get them to synchronize no matter what I did. I re-wired. I swapped the motor controllers. I swapped the circuit boards. I changed software. What I finally found was that the motors (stepper motors are electric motors that use 4-8 wires per motor and move with electric pulses) the motors were color coded wires - but they were just randomly color coded. The colors on one motor didn't match the next one. And they didn't match the paperwork that comes with them. They're actually easy to test and mark for what each wire does. But I spent a ton of time and effort on other stuff without considering that the wire colors weren't correct. So now I'm maybe extra cautious about the cheap chinese wiring.

These seemed so simple I thought it was obvious which wire came out where. So when I verified that visually it was wired correctly, I wasn't sure if it was possible to swap over internally, but I figured it had to be that based on the sensor reading indicating what was the reverse of what it should be. I thought it had to ether be an internal short in the sensor its self, or something in the plug. I started pulling on the wires on the back side and these are built with crimp on terminal ends that are then push fit into a housing, so you can wiggle them a little. I could tell at that point that the one I moved wasn't the one that I expected to wiggle.

So here's what it looked like inside when I pulled the back rubber seal off the plug. - Also, I couldn't release the terminal ends from the plug end. Usually you can use a release tool to pull the individual terminals back out and put them in the correct spot without cutting any wires, but for whatever reason I couldn't get them out without damaging it.

 

Again, good troubleshooting.