It's been a year of trouble free motoring with my 6.0, but yesterday I was driving down the road and the truck just went to an idle and won't respond to the throttle (gas pedal). Here are some pics of my AE scan. Numbers seem low, but the pedal seems to be working. 2 pics are with the pedal floored, and 2 are with it at idle position. Opinions?













Edit* Forgot to mention, the day before, i was pulling my "race" truck to the track, turned onto the highway, and tried to get up to speed, and it was way down on power, and the boost was at 32 lbs...it never goes over 27-28 after I had the PCM reflashed. I finally got it up to highway speed, started backing out of it, and all of a sudden it felt like it picked up a couple of cylinders, power came back, boost dropped and it was normal again. Don't know if it's related to this or not.

 

Pretty hard to read any of that

looks like a throttle/harness issue or p2285 is why the forced idle

I think either one will force limp mode

 

Yeah, the second picture sucks. It's not going over a volt and from what I understand, it should be at 5 volts at some point. And I just noticed the ICP code. I will check and make sure it's got 5 volts at the vref wire. Tomorrow. I'm burnt out from a race weekend...

 

Check ICPV at KOEO should be .18-.24volts

Unplug the ICP too and see if that makes it run better too

When you take sensor values you will do it at

KOEO
Low Idle
High Idle(2500RPM)

record sensor value for each^^so in the end you will have 3 Values per Each Sensor this will go for most all sensors Not just ICP Sensor

With me??

 

Yup, I'm with you, just have to go bale some hay first...rain is coming. And i guess I won't be able to get the high idle readings.
The wife said "Are you going to take it to the dealer?, I said no, then I will just spend a wack of money, and I won't learn anything.

 

Hay was at 33% so I had a little time to work on it. There doesn't appear to be ICP voltage, unless I'm reading it wrong. I'll try and post pics again, if they aren't readable I will just give you the numbers.
I unplugged the ICP and it didn't make any difference.
EDIT* just probed the vref wire and got 1.0 volts at KOEO

KOEO


KOER

 

wiggled all the wiring harnesses I could get my hands on while my kid watched the vref voltage, it never left 1.0 volts. Where does it get it's 5 volts from?

 

Anybody? Or anybody know where i can get a wiring diagram...goggle didn't get me anywhere.

 

Ya 5 Volts V-Ref

You had that 1.0V V-ref while truck was at Idle???

Diagram coming

 

wire diagrams
https://www.ford-trucks.com/ford-man...%20diagram.pdf

 

Yes, 1.0 volt at idle, KOEO, harness plugged into the ICP sensor or unplugged.
Can't read the diagram to see which one is the ICP sensor, but it looks like all of the(blue) 5 vref wires come from the PCM.

Edit* It looks like all of my v-ref wires have 1.0 volt - gas pedal, map sensor, icp sensor, that's why it was throwing codes for all of them.
How do I get 5 volts back?

 

I see a 0.01 volt reading at KOEO and KOER, along with the defaulted 870 psi DESIRED and ACTUAL readings. That engine must be running rough in that state.

Two of the three wires to the ICP sensor are spliced into EBP and EGR. And they would be the brown with white stripe coloured wire and the grey with red stripe coloured wire. Only one of the three wires is actually dedicated exclusively to ICP input, and that would be the dark blue with light green stripe coloured wire. A quick and easy test would be to unplug the ICP sensor, and either plug in a known good ICP sensor (or even an EBP sensor) to see if you get the 0.24 volt reading at KOEO. If plugging in a known good sensor gives you a reading, replace the ICP sensor. If plugging in another sensor doesn't change the voltage reading, check the dark blue with light green stripe coloured wire between the ICP sensor connector and pin #29 of the middle PCM connector for continuity.

In answer to your question about your accelerator response issue, you need to monitor all three accelerator pedal inputs on your live data monitor. Closed Throttle (accelerator pedal at rest) will produce the following readings from sensor A 0.8 to 1.1 volts, sensor B 1.4 to 1.6 volts and sensor C 3.9 to 4.2 volts. Wide Open Throttle should increase/decrease all three sensor readings in the same proportion to sensor A 3.1 to 3.5 volts, sensor B 3.6 to 4.1 volts and sensor C 0.7 to 1.2 volts. If any one or more of the sensor readings are not increasing/decreasing in the same proportion with change in the accelerator pedal position, the engine speed won't increase from idle.

 

The brown with white stripe coloured wire is your Vref circuit. Check it for continuity to ground. If you have continuity to ground, you have what's called a short to ground, which can and will definitely put the vehicle into forced idle only mode. On some vehicles, if this were the case the PCM would shut down. If you find you have a short to ground, begin by unplugging sensors one by one, until the short to ground goes away.

 

Awesome info Mike, thanks! I think the accelerator pedal potentiometer is ok, the numbers are way low, but I would think it's because it's only getting 20% of the voltage it's supposed to. All 3 sensor readings change as I push the pedal through it's travel.
I have NO readings at the ICP other than the 0.9 - 1.0 volt on the V-ref wire. I had quite a few issues last year with blown injector o-rings, and stand pipe o-rings failing, and I actually put pigtails into the two wires to make it easier to test with a multi meter on the side of the road, it would read around 0.56 with a hpop leak when cranking, now it reads nothing with the engine running or KOEO. The ICP sensor was just replaced last year when I busted the old one tightening it back in... I will buy another one if I have to, I will try the other stuff first.
I will try everything you told me tomorrow... I suck at things electrical, but I'm stubborn and cheap, so I'm hoping to win this battle.
And thanks Benny for your help too... you guys that post info on these forums have no idea how much you are appreaciated by us do it yourself guys!

 

Got it!! Unclipped the egr and tested v-ref, no change, unclipped the map, no change, walked around to the ebp... had had it in the back of my mind to check in that area... my degas tank started leaking a few days back... unclipped the ebp...tested the v-ref at the icp... 5.0 volts. The top of the ebp sensor was filled with coolant and shorting the harness out. 2ml of coolant brings the big white truck to a crippled halt.
Thank you Mike and Benny from a cheap and stubborn old fat guy!

Tried to rep you 2 but it told me I have to spread some love around before I can rep you again.