Code P0090

Mogman

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May 3, 2020
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I have my project running now and it is throwing some codes, I am a little confused is the 0090 code the fuel rail pressure sensor or the control valve?
Thanks
 

Mogman

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May 3, 2020
341
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Papalote, TX
I am sorry for before, anyone can have a bad day.
I do not seem to have continuity between the pressure valve connector pin 2 and the ECM (x1-24) so I just printed out the X107-108 connectors and am going to check there next.
 

Chevy1925

don't know sh!t about IFS
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what is every code you have? P0090 is fuel pressure regulator related, not the rail pressure sensor. You either have a sticky FPR, a bad coil in the FPR or no power to the FPR. you need 5v to the FPR for it to be controlled
 
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Mogman

Member
May 3, 2020
341
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Papalote, TX
what is every code you have? P0090 is fuel pressure regulator related, not the rail pressure sensor. You either have a sticky FPR, a bad coil in the FPR or no power to the FPR. you need 5v to the FPR for it to be controlled
Thanks! After re-seating X107 and 108 (for some reason were not fully seated, DOH!) that code went away after resetting the codes, the only codes I have now are a P16BC which looks alternator related a P0107 and some glow plug related codes. (am not running a glow plug controller)
I need to do a full load of a stock tune but am rather scared to do so, but because I do not have or ever will have the original DSP5 tune,, I guess there is just no way around it...
The transmission goes "into gear" (still on lift with no wheels mounted) but will not shift up and will only go to 20MPH (VSS live reading)

Edit, when tested on the lift before removing the power train from the wrecked truck it did shift up through the gears.

The original MAP sensor was toast in the wreck and I bought a cheap one, that may be the issue, although with a little throttle I am seeing 15 inches of boost on the live data, at least I think I am..
still a ways to go before that test drive.

EDIT, also found some transmission codes, evidently was only looking at engine codes, P0706, P0708, P0713 Also a U0073 communications bus off which may be related to the non communicating glow plug controller? I can see live transmission and engine data.

Feel like I am chasing my tail, guess it time to crawl under and check all the transmission connections.
 
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Mogman

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Plugged in the old MAP sensor and the P0107 went away, checked all the connections on the transmission and the P0706, 0708 and 0713 code persist.
 

Chevy1925

don't know sh!t about IFS
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Plugged in the old MAP sensor and the P0107 went away, checked all the connections on the transmission and the P0706, 0708 and 0713 code persist.

Look into the external harness where it goes into the trans at the back, make sure its connected fully. If so, ohm the wires at the internal harness where it connects to the NSBU back to where it connects to the external harness at teh back of the trans (back probe the wires at the external harness). if all that is good, may be a NSBU but being that everything worked prior to that, im more likely to say a connection issue. NSBU is on the inside of the pan on LBZ and up
 
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Mogman

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May 3, 2020
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Look into the external harness where it goes into the trans at the back, make sure its connected fully. If so, ohm the wires at the internal harness where it connects to the NSBU back to where it connects to the external harness at teh back of the trans (back probe the wires at the external harness). if all that is good, may be a NSBU but being that everything worked prior to that, im more likely to say a connection issue. NSBU is on the inside of the pan on LBZ and up
Thanks, I am looking for the connector view for the back of the transmission, cleaned and re-seated everything but did not help, I did find the connector view for the TCM, just a matter of looking more, checking continuity on that cable will be a pain, may just pull it out.
While the transmission did shift up through the gears I did not think to read the codes before pulling it, I need to get up to speed on the EFILive as I am using my old Autel code reader. I am not sure how much the guy who built the harness had to do to the transmission/TCM harness but ohming all the cable connections will be a start, looking at the TCM connector view/pin-out I do not see a fluid temp wire.
 

testdrive

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May 28, 2013
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two things to think about... is the trans in the manual mode and is the ECM thinking that it is in 4 wheel drive? In 4 wheel drive mode, speed is limited. of course the M mode would prevent upshifts
I have not gone back and read all of the past posts and these thoughts may not even be close. If I remember, you were dealing with a stand alone setup of some sort.
 
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Mogman

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two things to think about... is the trans in the manual mode and is the ECM thinking that it is in 4 wheel drive? In 4 wheel drive mode, speed is limited. of course the M mode would prevent upshifts
I have not gone back and read all of the past posts and these thoughts may not even be close. If I remember, you were dealing with a stand alone setup of some sort.
Something to look at, I have not made the serial connection from the transfer case controller to the DLC yet, not sure how the ECM knows what the transfer case is doing, I will have to look at it again I cannot remember if there was only the VSS cable to the T/C or if there was also a mode cable
 

testdrive

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May 28, 2013
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I should have written 4 wheel low range. And you are correct that you can go very fast in 4 wheel high.
 

Mogman

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May 3, 2020
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Papalote, TX
Look into the external harness where it goes into the trans at the back, make sure its connected fully. If so, ohm the wires at the internal harness where it connects to the NSBU back to where it connects to the external harness at teh back of the trans (back probe the wires at the external harness). if all that is good, may be a NSBU but being that everything worked prior to that, im more likely to say a connection issue. NSBU is on the inside of the pan on LBZ and up
Is the mode switch a "regular" switch? to say can it simply be checked with an ohm meter or is it a hall effect switch?
trans plug.JPG
parity.JPG
I just found the info on the TFT temp, I read this can be caused by low trans fluid, I am assuming because it will get hot if low, but it is in alarm when first fired up, but the fluid is a little low, just touching the beginning of the cold section on the stick
 
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Mogman

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May 3, 2020
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HAH!!! went to check the common wire on pin 58 of the TCM connector and it just pulled right out, now if I can figure out what the pin tool looks like so I can get the pin out
 

Mogman

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May 3, 2020
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THE MIL LIGHT IS OFF!!! and the transmission up shifts through the gears, YAY!!!
Now I get to start all over with a stock tune, the DSP-5 already had a bunch of deletes..will not be long now I hope..
 

Chevy1925

don't know sh!t about IFS
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Good to hear.

With as much as you have been here asking questions, why not post your build as well? lots of us like following along on transplant builds
 

Mogman

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May 3, 2020
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Here is the link, this swap is fairly well known and there are even kits to do it, but because I am hard headed and on a fixed income (retired thanks to the reaction to SARS-COV-2) and did not really care for how some of the conversions were done I decided to take my own route and see where it would lead, so there were a few re-think and change of directions along the way, I wanted to adapt the original cluster for example but found changes made with the introduction of the LMM made that rather difficult, 7 months or so and I am maybe a week or three from that first test drive.

 

Mogman

Member
May 3, 2020
341
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Papalote, TX
Well,, I did a full flash with a "stock" tune I got from a library and did the obvious deletes and now have two issues.

Before the flash when the engine was started the exhaust would sound very restricted, then after about 3 seconds or so it would "open up" and sound nice and throaty, it now stays in the "restricted" sound, kinda like the suction side of a powerful vacuum cleaner, not a pleasant sound.

The other is a U0073 bus code which I cannot find in the tune, of I did turn off the DTCs for the glow plug and BCM fail to communicate, also set the brake/traction controller to no MIL and display controller

I am a total amateur at the tune game for sure..

Maybe I am selecting the wrong status, for the BCM communications for example I put "non emissions no MIL" when maybe I should have put "not reported no MIL"

EDIT, the guy that built my harness says I need to add a 120 ohm resistor across the serial bus because I eliminated the glow plug controller, will report on that.
 
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