[Cgrigson1]

The Truck will just barely run at all and I just replaced the IPR and the ICP and it was running better before I did this. Just learned ICP voltage is supposed to be .24......PlUS I'm getting zero codes from my ScanGauge2.
A wiring harness is $630 and I don't have a clue if it will even fix it.

Question?
Does the power wire to the ICP run all the way thru the harness?
Is it possible for me to pull the harness off, inspect for chaffing and if I see chafing is it even remotely possible to trace the wire back after completely unwrapping the harness and then somehow get it all back together?

I'm about to pull my hair out over this damn truck.

 

[ford_doctor]

If you could provide specifics about your truck it would be helpful for those trying to help you: Model year, model, engine/trans etc. You can put t his info in your signature as well so it's permanent.


I am assuming you had this problem before you slammed an ICP sensor and IPR in it? Your ICP signal voltage reading is a concern and your specification of 0.24 volts KOEO is correct so there lies your problem. Technically, ICP readings KOEO can be anywhere from 0.15 to 0.35 volts to be considered in spec but typically around .24-.26 is normal. Have you performed any actual diagnostics? Do we have any codes to go by?

I would start by disconnecting the ICP sensor and inspecting the pins for damage, corrosion... then with a volt meter check for reference voltage at the VREF circuit at the sensor - the brown/white wire. If low, unplug the EBP sensor and EGR valve to see if either of them is pulling the voltage down and move the harness around going from the sensor all the way back to the PCM. If still low, then check the continuity of all three circuits from the sensor to the PCM.

I attached the wiring diagram page from the 2005 manual to help you but the wiring has changed a couple of times depending on model year so I will change the image to the correct year if you can provide that information. It makes a difference!!!

 

[Cgrigson1]

ICP VOLTAGE LOW

Man I super appreciate your help!!!
The truck is an early 04, problem started after I replaced an injector plug, #8.
I am getting absolutely zero codes on my scan gauge except for the one saying where the hell is my EGR cooler. Hard deleted.
I do feel like I have a weak Hpop because it takes a bit for it to build up pressure but I'm wanting to see about all that once I figure this
Issue out.

I will EBP sensor and then so I recheck the voltage at my ICP plug? Assuming same with the EGR valve. Also I won't know what pins to use to ck the PCM end for continuity. I paid for the all data diy deal but man it is not user friendly and couldn't find what I was looking for.

Thanks again!
Clay
Dallas, TX

 

[ford_doctor]

Here are the correct diagrams for your 2004 6.0L. I included the PCM connector face diagram for you as well. Connector C1381c is the middle connector on the PCM.

Verify the circuits as we discussed and add the throttle position sensor, EGR and EBP sensors if you need to disconnect or measure voltage at those sensors. It does not matter if the EBP sensor was deactivated with the engine calibration from an early recall - the circuits are still connected and can cause problems. (in case anyone is wondering)

An early 2004 engine should have the ICP located on the HPOP cover in the rear of the engine. They were known for ICP sensors that often damaged the harness and connector due to oil migration. Inspect that connector and wiring - if damaged replace the connector with a service pig-tail.

Since you were repairing the injector harness at #8 you were working right in the same area so reinspect your work in case you caused this problem by damaging something accidentally. You said this started after that repair right? It happens.

As for the HPOP, the early pumps are a high failure rate item. BUT the pump won't affect your KOEO voltage. I am getting the impression you know that though.

 

[Cgrigson1]

Thanks

We are having weather issues here so I might not get to look into this for a few days. My ICP sensor is near cyl 1 very easy to get to fortunately but my IPR that I changed out was on the top of the HPOP. Thanks for the diagrams I'm sure that will make a big difference for me.
Thanks again!
Clay

 

[ford_doctor]

Then it is not technically an early 2004 if the ICP is on the right valve cover. Soooo we revert to the prior diagram...

 

[Cgrigson1]

Ok

Yes its on passenger valve cover towards the front
I'll assume the pin diagram for the harness at the CPU will be correct

 

[Cgrigson1]

Doesn't look like its gonna rain today, was gonna go deer hunting but plan to start looking at the truck here in a bit.
Thanks again I'll let you know what i see. First order of business is for me to look at a ford website that I feel like will show me where these other sensors are you mentioned.
Thanks
Clay

 

[Cgrigson1]

Now I don't see the previous diagrams in the thread suddenly??? I'm going to send you something for your time if we get this figured out for sure!

 

[ford_doctor]

I changed back to the original in the lower post. Has no highlighting. Its basically the same. And ahh, Doc participates in these forums to give back... its no trouble at all and there are dozens of others who give of thier knowledge freely. That is what this community is about

 

[Cgrigson1]

Oh Sir the highlighted diagram of the connector at the CPU was awesome. Exactly what I needed! I got a late start on it this afternoon and did remove some tubes to make the harness more accessible and moved it around and inspected what I could inspect with it being still plugged in and didn't see anything obvious. Then I unplugged EBP which was first in line from the CPU and no change in voltage. I feel I need a buddy to come help ck continuity on the ICP plug. I have a long wire with alligators on it but I fear damage to pins or connectors which would compound my issue. I'll see based on all the rain we're supposed to get what progress I can make.
Thanks again for your help Sir.
Clay

 

[Cgrigson1]

I made a discovery

Ok. So I got back into working on the truck today and I did verify continuity of the ICP wires from pcm plug to the pigtail to be good BUT I ckecked the Reference voltage where the wire comes out of the pcm plug and still only .01 at that point which tells me it's not the wiring harness. Is there a way to test pcm's? Do you feel like this is my problem? I went down the harness unplugging things and ck'ng for a difference but there was no change. Could another sensor or some short potentially somewhere cause the computer to send such a low voltage to the pcm?
Thanks again for all your help!

 

[Cgrigson1]

ICP voltage

And getting .05 at the pin coming out of the CPU KOEO