[regginator]

Hello all. I fix one thing and another pops up on this truck and here is the latest thing I can’t figure out. I lost the CP4 on my truck last summer. Ordered everything and replaced CP4, injectors, lines, rails and all that. Also did a SPE disaster prevention kit while I was in there along with an egr delete and ccv reroute. Dpf is still on the truck but emissions are turned off with a mini maxx. I want to make Sure it’s running fine before I spend more money on a delete pipe. After a headache of months waiting on parts that got shipped wrong I finally got the truck put back together and running a month ago. Had a P0193 code and was running rough. Got busy with work so it sat in my shop another month but finally was able to take it in to get the flow rates For the injectors done this week. Truck ran decent on the way to town to get injectors programmed (10 miles) but in reduced power mode from P0193. Had them trouble shoot that while they had it for injectors and they came up with shorted to voltage. I picked the truck up and went to the gas station to put some fresh fuel in it and drove it back to my shop. Truck runs fine now but still in reduced power and has to turn over longer to start. I unplugged the FRP sensor and have 5volts on grn/vlt signal wire and 4.5 volts on blue/vlt return wire. Psi is maxed at 31.5k psi with the sensor plugged in or unplugged. I unplugged two of the three connectors from the PCM, I left the main power connected, plug furthest to the passenger side, and had 4.5 volts on the return pin and harness from sensor plug back to PCM is in good shape. No bad spots and ohms good. I ohmed every other pin back to that return pin to try to see where it was coming from but there’s no continuity between anything. Does this sound like a short in the PCM or will a shorted wire or shorted sensor on the same vref feed through the pcm like that? First issue I had with the truck last summer when I bought it was the ac compressor was intermittent and then stopped working and I know that the FRP and ac system are on the same vref but I had no fuel related issues/codes up until it died on me when the pump went. Currently Still have the P0193 but that is the only code. Any insight or schematics would be greatly appreciated before I pull out the rest of the little hair I have left. Thank you.

 

[FordDoctor]

Sounds like you have a pretty good grasp on this already. Just to be clear - the FRP signal circuit is VE727 Blue/Brown. Consult the diagram below. Just double check you are testing the correct circuit. The FRP signal is a stand-alone circuit therefore should have 0 volts when measured at connector (disconnected) C1360 pin #2. I always question why our pinpoint tests have us check for a short in the harness with the PCM disconnected - a short is most likely going to occur in that harness. Testing that way will only find a short to VPWR (12volts) as FREF (5volts) comes out of the PCM. You apparently have a short to VREF based on your voltage reading. With that said, if you are confident in what you have tested thus far, isolate the FRP circuit coming out of the PCM connector - unwrap the harness some. Cut it keeping in mind you will need to restore that break in the wire. Check for voltage on both sides of the cut wire with the FRP sensor disconnected and the key on. That will tell you for certain whether it's the PCM or the harness. It is VERY rare for a PCM to fail... but it does happen once in a blue moon.

 

[regginator]

Yes that’s the right circuit sorry. I thought it was blue/vlt but it is the blue/brwn wire. I have cut that harness apart, along with pretty much every other harness there is access to. The blue/brwn wire looks and ohms good. With the pcm unplugged there is no short on that wire. With the plug out of the way, I checked pin 21 (vref) coming out of the pcm with KOEO and there is 5volts. What’s weird to me is I also checked pin 15 (frp sensor) coming out of the pcm and there’s 4.5volts on that pin. With it unplugged, Pin 15, at the pcm should have 0 volts on it correct? Thanks for your help.

 

[regginator]

So to make my confusing jabber to the point, instead of cutting the wire I just unplugged the plug and checked the pins at the pcm instead. That’s where I had 4.5volts is on the pcm pin.

 

[regginator]

Another bit of information is after sitting in my shop from July to December, when I first tried to start the truck up after the new fuel system, batteries were pretty much dead. Put the charger on them and got the truck started. Last night after I left the key on, all accessories off, for an hour or so while I was trouble shooting I went to start the truck up and turned over once and then clicked. I now have a “intkey could not program” message. So my batteries are shot. that’s where I stopped until I get new batteries in it. They tested good back in June when I was trying to figure out the AC issues I was having. I know batteries that aren’t 100 percent will wreck havoc on these trucks as I had a bunch of weird issues with my dads 2011 and it ended up needing new batteries. His tested good at multiple stores. I’m buying new batteries this morning and though I don’t think new batteries will fix this issue, I can’t help but think the bad batteries shorted out the pcm.

 

[FordDoctor]

So to make my confusing jabber to the point, instead of cutting the wire I just unplugged the plug and checked the pins at the pcm instead. That’s where I had 4.5volts is on the pcm pin.

So, you are saying that with the PCM disconnected and the FRP sensor disconnected, you have 4.5 volts on circuit VE727 both at PCM connector pin 15 and FTP sensor pin 2?

 

[regginator]

No sorry. With pcm disconnected and frp disconnected there is no voltage at the connector or anywhere in the harness. Just have 4.5volts at pcm connector pin 15.

 

[FordDoctor]

No sorry. With pcm disconnected and frp disconnected there is no voltage at the connector or anywhere in the harness. Just have 4.5volts at pcm connector pin 15.

Where are you testing? The PCM pin directly or are you back probing with the connector connected?

 

[regginator]

Pcm pin directly. Pcm plug was unplugged.

 

[02_7.3]

Im sure your aware, but you really shouldn't be running that dpf on with it being tuned. Think how often these Regen stock. Add tuning that is going to create more soot is going to clog it up even faster. Not good if the truck has to fight a clogged dpf.

 

[regginator]

I am aware but I’m not going to spend another 500 bucks on an exhaust until I know this truck is running right and I’m not worried about a plugged dpf from 30 miles running 45 mph with a derated truck on a stock tune. I’m not running it down the highway I just had to get to a more capable shop that can program the flow rates. I really didn’t plan on deleting it but didn’t want to mess with putting the egr back on and already had an egr delete kit and mini maxx in my tool box that I didn’t end up using on a previous truck from way back. It seems like I remember a way to go in the mini maxx and turn the egr off but leave the dpf on but I couldn’t find it. It’s been a while since I’ve messed with deleting and tuning trucks.

 

[scottu5]

I am aware but I’m not going to spend another 500 bucks on an exhaust until I know this truck is running right and I’m not worried about a plugged dpf from 30 miles running 45 mph with a derated truck on a stock tune. I’m not running it down the highway I just had to get to a more capable shop that can program the flow rates. I really didn’t plan on deleting it but didn’t want to mess with putting the egr back on and already had an egr delete kit and mini maxx in my tool box that I didn’t end up using on a previous truck from way back. It seems like I remember a way to go in the mini maxx and turn the egr off but leave the dpf on but I couldn’t find it. It’s been a while since I’ve messed with deleting and tuning trucks.

For the mini max. Go back into menu (programming) and one of the options will be ‘stock’ (or something similar? Like factory setting?)
I installed mini max on my truck (not deleted) and didn’t realize I loaded a ‘tune’ (but my truck stopped regen process)..so I went back into the menu and returned it to stock / factory setting.

 

[FordDoctor]

Pcm pin directly. Pcm plug was unplugged.

That approach is not a "best practice" for testing and those pins in the PCM connectors are extremely easy to damage.

Anyhoo - back to your problem. You should not have voltage on circuit VE727 with the FRP sensor disconnected. You tested the wiring and found no concerns. With 4.5 volts coming out of the PCM on that circuit VE727 then yes, you likely have a faulty PCM. The pinpoint test do not lead to replacing the PCM for a short to voltage after testing and verifying the circuits for the FRP, the direction is simply to "repair the circuit." Well, the PCM is part of that circuit. Before you condemn it, restore all electrical connections, clear the codes and run the engine and see if the symptoms, check engine light and code all return before proceeding.

I also went through my forums and other sources for this code and all were related to concerns on the VREF circuit which is not the case here but worth mentioning. Notes include harness chafing and damage around the EGR cooler gasket where the bypass/EGR valves mount and at the DPF pressure sensor mounted on top of the exhaust filter. Those concerns would likely cause codes for multiple sensors due to a loss of VREF.

Let us know how you make out.

 

[regginator]

I’ll keep that in mind on those pins. They are very small and I could see them bending if not being very careful. I just wanted to go straight to the source to get rid of any other variables. I did check the egr and dpf wiring as well as harness under both wheel wells as I’ve read those can be problem area’s. Haven’t found anything yet but I’ll check it again. I’ve got access to my dads 2011. Can I pull the pcm from that and try it in this 2011 to see if that voltage goes away? I’ve read there is some programming that needs to be done when changing a pcm. Thanks for the help!

 

[regginator]

For the mini max. Go back into menu (programming) and one of the options will be ‘stock’ (or something similar? Like factory setting?)
I installed mini max on my truck (not deleted) and didn’t realize I loaded a ‘tune’ (but my truck stopped regen process)..so I went back into the menu and returned it to stock / factory setting.

I do know how to return it to stock but my egr is gone so I can’t do that. I have no problem taking the dpf off I’m just waiting until everything else is good first.

 

[FordDoctor]

The engine harness really does not go anywhere but the engine and the PCM.

Added: if this were a VREF circuit concern that leg of the VREF is bussed inside the PCM and does include body harnesses.

 

[scottu5]

I do know how to return it to stock but my egr is gone so I can’t do that. I have no problem taking the dpf off I’m just waiting until everything else is good first.

Yes sir, after I wrote that, went back and read your original post and saw you had the EGR deleted. My bad, sorry ‘bout that.

 

[regginator]

The engine harness really does not go anywhere but the engine and the PCM.

Gotcha. If I end up needing one, Will any pcm work or do I need to find a specific number? I see pcm’s anywhere from 500-600 bucks online. And will the truck run at all with the new pcm or will it not start until everything is programmed?

 

[regginator]

Can I use any pcm or does it have to match my specific part number and hardware code? I found a reman matching numbers to mine that is supposed to be plug and play other than the pats, but my neighbor happens to have a 2011 f250 6.7 that he’s parting out. I know it would have to go to the dealer to be programmed but I’ll probably have to go to the dealer to program the pats system anyways even with the reman plug and play pcm.

 

[Hydro]

I am thinking that the way you measured the vRef voltage, that there is not a problem with the PCM
really thinking this is a false trail to follow -- but time will tell if I am right

Does your scan tool show that the vRef voltage is low, with everything connected ?

With it unplugged, Pin 15, at the pcm should have 0 volts on it correct?

Not necessarily, ...you should test this with the connector in place, and using back pin to check that voltage
Would be interesting to test your "new" PCM here to verify if that pin has voltage or not