Beings i cant post in tech files...

[PowerstrokeTech82787]

Figured id put up another help guide and make one of the worst or seemingly worst case scenario like i have run into today, make it a 10 minute job vs HOURs of poking and prodding with a back probe and DVOM by load testing circuits.
This is for trucks pulling multiple LOW circuit codes.

Okay, so i got a poor souls 6.0 that has been to 6 different dealerships in this past month ALONE. The guy is fed up, and the premadonna(aka other diesel tech) refuses to touch it because its a rusty 05. Hey its a work truck what do you expect. Its had a complete engine harness put in, throttle pedal installed, egr valve installed map sensor and hose, intake cleaned at a machine shop, turbo replaced ICP sensor replaced, pigtail installed, these other dealerships CARPET BOMBED it and didnt fix it, when the last place wanted to throw PCM in it the guy threw his hands up and said hes had enough so he brought it to us. Which gave me a chuckle. I admit im not the best and brightest tech when it comes to electrical issues. Believe it or not all you need is a couple jumper wires, and a light socket for a license plate light and the ability to disconnect connectors. maybe some tools to remove things to gain access to sensors/connectors/splices and a wiring diagram.

Issue-No throttle, forced idle.

What i found with IDS would be enough to make the average joe cringe and run for the hills.
Actually have the RO found it curled up in my pocket.
here we go...

Codes i got were
P2138 APP Throttle/pedal position sensor/switch D/E voltage correlation Difference in sensor readings
P2139 APP Throttle/pedal position sensor/switch D/F voltage correlation Difference in sensor readings
P2140 APP Throttle/pedal position sensor/switch E/F voltage correlation Difference in sensor readings
P0069 BARO MAP/BARO correlation MAP/BARO, EP must be within 1 psi
P0500 Vehicle Speed Sensor
P0236 MAP Turbo/supercharger boost sensor A circuit range/performance Restricted exhaust, hose missing
P0237 MAP Turbo/supercharger boost sensor A circuit low Circuit open, short to ground, faulty sensor
P0299 EP Turbo/Supercharger Underboost EP actual is less than commanded
P2285 ICP Sensor Circuit Low
P2287 ICP Intermittent Circuit fault
and every single EGR Code...
With the KOEO the trucks boost gauge would creep up to 20PSI of boost.

First step in this equation of Cluster fock Find something that ALL these sensors have in common and verify there is no blown fuses.
which is in this case the VRef (reference voltage 5v from pcm) and signal return.

This would now be where you would turn to your wiring diagram.
Find what pins of the connectors are what. Start from the one end of the circuit, in the diagram the circuits are numbered. So you can find what circuit is what and look what pin it is at the PCM connector, do not be confused if there is a change in the circuit number, because there are splices.

Okay so what i did was unplug the pcm connector, and the throttle position sensor. Put a jumper wire with full 12v to the pin number 33 of the PCM connector which would be your Signal Return wire. (The circuits in this scenario all share the same VRef and Sig Return wires despite the change in the circuit numbering due to a splice. S170.) Now the ground which will be the light went to the pin for the APP sig return wire. It was very very dim. This indicates a short somewheres in the circuit. Next step is to unplug 1 by 1 every other sensor to elminate a shorted internally shorted sensor and go from every sensor in order from furthest from the PCM to nearest. what your doing is load testing the circuit at its connectors to verify its NOT in the harness inbetween the sensors. I know it had a new harness installed but being it was carpet bombed... you dont know who last mollested it, and you dont know if they may have damaged anything in the process of installing a new turbo or whatever else... So i verified the circuit was good so now time to test the sensors out individually.

Heres what you do. Unplug 1 sensor at a time with the key off. Then start it. If the wrench light is still on and no throttle response, you know its not that sensor. So when i unplugged the EBP sensor and viola the wrench light went out and i could rev it til it bounced off the rev limiter, that indicates an internal short of the EBP sensor. They replaced everything except the EBP sensor. usually when i see a low boost code i start right off the bat with searching for carbon on the fire wall, and on the heads, and then pull the EBP sensor and check the tube on how carboned up it is. but this didnt happen to be the case. Yes ive seen the accelerator pedal positioning sensor fail before, but when the pid i viewed on IDS shows the throttle at 83% without touching the pedal, and the other 2 showing what it should be without the pedal being applied, i would say the same thing... but id go further than just whip parts at it.

This customer is going to be going after the previous dealerships for $ and i wish him the best of luck.

so remember if you have a LAUNDRY list of codes, and they are circuit fault codes, stay calm, ask for wiring diagrams, and anything pertaining to circuit in question and you can do it.

[ianstew]

nice diagnostic work.

[Ryan Rønning]

Thats good stuff right there.

I have to ask though. What is carpet bombing. I have an idea but am not sure.

[PowerstrokeTech82787]

Originally Posted by Ryan Rønning

Thats good stuff right there.

I have to ask though. What is carpet bombing. I have an idea but am not sure.

carpet bombing. kinda like what we do in afghanistan when we cant find the rotten cave dwellers.

Carpet bombing is throwing parts at it until you finally replace the one that fixes it. But its okay, you know everything for that system is new so you shouldnt see the truck back for quite some time right?! something that happens often especially if its a truck that goes from one dealership to another.

[dannyboy950]

Now this is a driveability tech

[Cuzmail]

Dude, I love your posts. Common sense isn't so common these days.

Please don't get banned somehow!!!!!!!!!

Shawn

[HAM_RADIO_MAN]

Originally Posted by PowerstrokeTech82787

carpet bombing. kinda like what we do in afghanistan when we cant find the rotten cave dwellers.

Carpet bombing is throwing parts at it until you finally replace the one that fixes it. But its okay, you know everything for that system is new so you shouldnt see the truck back for quite some time right?! something that happens often especially if its a truck that goes from one dealership to another.

We call it shotgunning parts. IF you throw enough parts at the situation you will hit the problem at some point. On a 6.0 this will leave a guy broke and frustrated.

[PowerstrokeTech82787]

Originally Posted by dannyboy950

Now this is a driveability tech

its all i do all day every day. 6.0 6.4 6.7 and when its something the premadonna doesnt want to do and i have to do it reluctantly-a 7.3 (hate 7.3s too vague with codes so i approach them as i would a TBI or carbureted engine)

Originally Posted by Cuzmail

Dude, I love your posts. Common sense isn't so common these days.

Please don't get banned somehow!!!!!!!!!

Shawn

Haha i always seem to sh!t in someones hat bad enough to be threatened to be banned. i still got emails from tons of people for help and all of them thought that it was unfair that i got banned. Guess if you got a petition to go around to make me ban proof

BTW Merry Christmas everyone!

[sargar]

Good info. I had wanted to comment on another post of yours and didn't...so here goes.

What really sucks in the dealer world as well as the independent world, is the fact that the people who couldn't find their butt if you let them use both hands (your premadonna) get all the gravy. This leaves the guy(s) that can fix stuff rather than just replace parts stuck with all the crap that doesn't pay as well. What is even worse is when you have to mop up after your premadonna and argue with your svc manager to get paid on it. I own my own shop now but I have always said that if I ever have to go back to a dealer I am only taking a tackle box with 2 screw drivers and a rusty pair of pliers with me, that should run me to the top of the pay scale pretty quickly.

[PowerstrokeTech82787]

Originally Posted by sargar

Good info. I had wanted to comment on another post of yours and didn't...so here goes.

What really sucks in the dealer world as well as the independent world, is the fact that the people who couldn't find their butt if you let them use both hands (your premadonna) get all the gravy. This leaves the guy(s) that can fix stuff rather than just replace parts stuck with all the crap that doesn't pay as well. What is even worse is when you have to mop up after your premadonna and argue with your svc manager to get paid on it. I own my own shop now but I have always said that if I ever have to go back to a dealer I am only taking a tackle box with 2 screw drivers and a rusty pair of pliers with me, that should run me to the top of the pay scale pretty quickly.

premadonna can fix anything 7.3s 6.0s etc. BUT he calls the shots has a worse attitude than me when something gives him a problem like one time he got a bad radiator out of the box from ford for a 6.4 he put it all together i suggested him to use my vac filler and pressure test it he was all like RAH DONT TELL ME WHAT TO DO I BEEN DOING THIS SINCE YOU WERE IN 8th GRADE! well he goes out road tested and had a coolant leak when he came back. He ripped that front end apart parts went flying everywhere and he tore the radiator hoses attached clean out and wung it on the floor got a sledge hammer and beat it to death, then left a nasty message on it with permanent ink, damaged the shrouds and everything.

Plus he has all the special service tools that belong to the shop locked in his box so if you have to do something that needs a special tool and hes not there or hes got a grudge with you for what ever reason, he tells you to buy your own or your tied up because hes got the tool locked in his box. Thats okay. I buy my own, eventually ill have everything for 6.0s and 6.4s and when my taxes come in ill have my own IDS soon since he punched the screen on the laptop and you can hardly see what your looking at it plus the battery doesnt last for crap so when i have mine and the shops dies and he wants to borrow mine ill tell him buy your own

He calls the shots only because hes fully certified i only have 6.0 6.4 certs, and beings theres only 2 of us diesel guys and the amount of trucks we work on i dont have the chance to get fully certified... even though i dont want anything to do with hybrids and cars hate working on ford cars they are the worst put together vehicles ever! except for towncars and crown vics. ill work on them willingly. Mustangs, F150s fusions, focus's, nope wont touch them no room. I will wreck more than ill fix.