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Code P051D

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2021 Explorer ST
#1
Hi all, So Ill try to keep it short, I just had my 1st revision from ZFG uploaded 93 performance tune and the next morning I noticed a CEL on, hooked up the checker and its saying code P051D Crankcase pressure sensor circuit high and a misfire code P0316, has anyone had any experience with these codes? Im thinking its not tune related due to the fact the explorer has 67000 on it I think the tune just "helped" the gremlins to show there face. Just had sparkplugs done too about a week ago. thanks in advance!
 

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Black 2020 ST
#2
What mods have you done?
 

OP
21STBlkout
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Thread Starter #3
So Ive done whipple intercooler, CV 3 inch High flow cats (with defoulers), full thermal 2.5 exhaust and then the tune from ZFG
 

OP
21STBlkout
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Thread Starter #4
So looking more into this, it looks as if I dont have a crankcase pressure sensor on the PCV hose. So where is the sensor if that is what the code is telling me? Is it in the ECM?
 

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#5
OP
21STBlkout
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Thread Starter #6

Cajun Heat

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#7
So Ive done whipple intercooler, CV 3 inch High flow cats (with defoulers), full thermal 2.5 exhaust and then the tune from ZFG
How long were you running the other mods before doing the tune?
 

OP
21STBlkout
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Thread Starter #8
About a month give or take. Had no signs of issues until I uploaded the 1st revision on Friday last week and got the CEL later that day, I dont think its the tune though not sure I think something just finally went after I tuned it, Doing more info digging Im thinking bad PCV? I have an e-mail into Adam over at ZFG to see if maybe he can give me some feedback too.
 

Last edited:
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2022 ST
#9
I would call ZFG and tell them what's going on.
From what you said: You have a crankcase sensor error firing when you don't even have that sensor, and it only started happening after you installed the tune.
The first rule of troubleshooting - if something started acting weird only after you touched something - undo what you did/check how you broke it.

I'm thinking you might be an exception as to how early that crankcase sensor was removed, and you have the wrong tune.
 

OP
21STBlkout
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Thread Starter #10
I would call ZFG and tell them what's going on.
From what you said: You have a crankcase sensor error firing when you don't even have that sensor, and it only started happening after you installed the tune.
The first rule of troubleshooting - if something started acting weird only after you touched something - undo what you did/check how you broke it.

I'm thinking you might be an exception as to how early that crankcase sensor was removed, and you have the wrong tune.
Ah I see what your saying, ZFG may have tuned it thinking I have the sensor? correct me if Im wrong. Possibly where the misfire code may be coming from too. I do have an e-mail out to ZFG/Adam so I will see what feedback he gives me, thanks for the help as well.
 

OP
21STBlkout
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Thread Starter #11
So update, I just returned it to stock and the CEL is gone (checked for codes as well, none) so Im leaning to the fact it was tuned thinking it does have the crankcase position sensor, I let ZFG/Adam know as well so we will see what the next steps are.
 

Cruising68

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#12
Nice. Now you know. I’m sure it will get resolved. I love mine and have had zero issues other than a shit eating grin on my face sometimes


Sent from my iPhone using Tapatalk
 

OP
21STBlkout
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Thread Starter #13
Nice. Now you know. I’m sure it will get resolved. I love mine and have had zero issues other than a shit eating grin on my face sometimes


Sent from my iPhone using Tapatalk
Im keeping my fingers crossed, but im pretty sure thats the issue just waiting for a reply from ZFG/Adam. And yes when I first uploaded the tune it was soo awesome I was laughing the whole time taking it for a quick test drive LOL. So much more acceleration and the shifts were soo damn smooth!
 

OP
21STBlkout
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Thread Starter #14
So just an update, I received the revision from ZFG/Adam this morning and wrote it to the explorer, no CEL or misfire, so far I was just able to do a short drive to work so I will give it a few before I send the logs (0-60 and 3rd gear pull) to Adam just to make sure it was in fact the crankcase position sensor issue, On a side note I have to give props to ZFG team/Adam for the quick turn around time to get me the fixed file awesome customer service and Im very happy so far, Im pretty sure I wont be getting the CEL now.
 

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2022 ST
#15
That is great news.
I'm glad to hear you were able to get it straightened out.
Thanks for including the background information for what all was going on with your ST at the time you had the problem, it made it very easy to troubleshoot. :cool:
 

OP
21STBlkout
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Thread Starter #16
That is great news.
I'm glad to hear you were able to get it straightened out.
Thanks for including the background information for what all was going on with your ST at the time you had the problem, it made it very easy to troubleshoot. :cool:
No problem at all, and thank you all for the help as well it made my issue that much quicker to resolve. Ill keep everyone posted in the next few days!
 

OP
21STBlkout
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Thread Starter #17
Got the OK e-mail from ZFG/Adam that the data logs look good, no CEL's. Wanted to thank everyone for there help again here!
 

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#18
Got the OK e-mail from ZFG/Adam that the data logs look good, no CEL's. Wanted to thank everyone for there help again here!
That's great news! Congratulations on your new (fully working) tune!
 

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#19
Glad it got sorted out. (y)
 

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21STBlkout
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Thread Starter #20
Not sure if I should of started a new thread or not but, is anyone tuned and needed the FADA upgrade done? (leaking and throwing codes) would I need to go back to stock for my garage to update the AWD module to the latest software for the new part? thanks in advance!
 

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