Just finished doing an afm delete on a 2014 sierra l83 with a LOT of help from clinebarger.It fired up quickly with almost immediate oil pressure and runs smooth as silk but the check engine light is on and codes P0300 and P0138 are showing as permanent on the scanner.I ran it for 20 minutes so the new springs would break in properly and watched everything for leaks ,temp,oil pressure ect and all good.The afm function was shut off prior to me getting truck with an hp tuner.I understand that even though its shut off i need more done via the tuner and i'm wondering if these codes are part of it .I'm very limited in my tuner knowledge and i live in a small area in NB Canada where nobody i have talked to has done one of these deletes.Diesel deletes are common place as we are a farming area but the gassers just get put back to oem so the bombs keep on ticking lol.I know a guy who does some stuff with an hp tuner but he has never been into one of these and not sure if he even will.Am i going to hurt the motor by running it until i can get this figured out.Ps could not enough backpressure cause the o2 code as a previous owner removed the muffler which i haven't addressed yet?
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L83 AFM Delete DTC P0300 & P0138
- Thread starter duffy
- Start date
clinebarger is the man!
I'm not big into Gen V stuff, more Gen III. But a few things come to mind.
- Your DOD delete, is your new cam a pretty mild/stock-ish cam? If yes, it should run OK on the factory calibration once DOD/AFM and or VVT is disabled. If you have a pretty big cam, you may need to de-sensitize the misfire tables as anything beyond a factory smooth running "waveform" the thing thinks its misfiring.
- Any time you change any piece of the rotating assembly, it is critical on an Gen III/IV LSx to perform a cam/crank sync relearn -- I would imagine Gen V LTx is the same thing. It should be a function within VCM scanner (HPTuners) or on any decent scan-tool. Being a K2xxx truck, it is definitely in GM GDS.
Without doing a cam/crank sync on a Gen III, you'll throw P0300 all the time, but it will run OK.
I have nothing to add on the O2 code, but see if you can get the P0300 gone first. I'm sure clinebarger will comment with some awesome info. I always feel bad buggin' the guy but man is a wizard.
I'm not big into Gen V stuff, more Gen III. But a few things come to mind.
- Your DOD delete, is your new cam a pretty mild/stock-ish cam? If yes, it should run OK on the factory calibration once DOD/AFM and or VVT is disabled. If you have a pretty big cam, you may need to de-sensitize the misfire tables as anything beyond a factory smooth running "waveform" the thing thinks its misfiring.
- Any time you change any piece of the rotating assembly, it is critical on an Gen III/IV LSx to perform a cam/crank sync relearn -- I would imagine Gen V LTx is the same thing. It should be a function within VCM scanner (HPTuners) or on any decent scan-tool. Being a K2xxx truck, it is definitely in GM GDS.
Without doing a cam/crank sync on a Gen III, you'll throw P0300 all the time, but it will run OK.
I have nothing to add on the O2 code, but see if you can get the P0300 gone first. I'm sure clinebarger will comment with some awesome info. I always feel bad buggin' the guy but man is a wizard.
Perform a CKP relearn first as Redhat mentioned.
P0138 is high voltage on bank 1 sensor 2, You have a way to read scan data?
P0138 is high voltage on bank 1 sensor 2, You have a way to read scan data?
My son was going to borrow a laptop scan machine from a place he does s little truck work for.It’s supposed to be a good machine but i know jack **** about that stuff.Will this relearn be one procedure or do you do it for both the crank and the cam separate?Clinebarger i sure appreciate your help on this and so far it looks promising as it runs real smooth.This tablet thing he’s bringing home should work as long as i can find the right function to get into.Be nice to get this behind me so i can get back at my Cat eye duramax build.It’s been nice getting advice from hands on people instead of someone that read something somewhere and advising you as if they had real world knowledge.
Yeah it’s a mild cam i just put the L8T in so basically stock as i didn’t want to get into a tuning problem.People here tend to get tuning done away from here and i’m not smart enough to buy a tuner and then do any programming with it.clinebarger is the man!
I'm not big into Gen V stuff, more Gen III. But a few things come to mind.
- Your DOD delete, is your new cam a pretty mild/stock-ish cam? If yes, it should run OK on the factory calibration once DOD/AFM and or VVT is disabled. If you have a pretty big cam, you may need to de-sensitize the misfire tables as anything beyond a factory smooth running "waveform" the thing thinks its misfiring.
- Any time you change any piece of the rotating assembly, it is critical on an Gen III/IV LSx to perform a cam/crank sync relearn -- I would imagine Gen V LTx is the same thing. It should be a function within VCM scanner (HPTuners) or on any decent scan-tool. Being a K2xxx truck, it is definitely in GM GDS.
Without doing a cam/crank sync on a Gen III, you'll throw P0300 all the time, but it will run OK.
I have nothing to add on the O2 code, but see if you can get the P0300 gone first. I'm sure clinebarger will comment with some awesome info. I always feel bad buggin' the guy but man is a wizard.
The CKP relearn, teaches the PCM the rotational relationship between the reluctor wheels/pickup teeth on the crankshaft and camshaft. It is just one procedure.
Whatever scan tool (or maybe a GDS laptop) you use, it will more than likely tell you to set the parking brake, turn the vehicle off, then on, etc. Follow those instructions to a "T". They are instrumental in telling the PCM that you're performing that function. If you go to do a relearn and the engine revs up to 6K or so... it is not doing a CKP relearn. When doing a CKP relearn, they'll hit fuel cut at a much lower RPM, maybe 3-4k?
EDIT: Just to give some more info, when I say GDS laptop -- Global Diagnostic System 2 by GM. It is a piece of software from GM that is installed on a Microsoft Windows-based computer that is GM's current dealer-level scan tool. It is a part of GMs "suite" of vehicle diagnostics/programming which is called TechLine Connect. I just wanted to explain what that was. I would expect most Snap-On or Autel scanners to be able to do the relearn.
Whatever scan tool (or maybe a GDS laptop) you use, it will more than likely tell you to set the parking brake, turn the vehicle off, then on, etc. Follow those instructions to a "T". They are instrumental in telling the PCM that you're performing that function. If you go to do a relearn and the engine revs up to 6K or so... it is not doing a CKP relearn. When doing a CKP relearn, they'll hit fuel cut at a much lower RPM, maybe 3-4k?
EDIT: Just to give some more info, when I say GDS laptop -- Global Diagnostic System 2 by GM. It is a piece of software from GM that is installed on a Microsoft Windows-based computer that is GM's current dealer-level scan tool. It is a part of GMs "suite" of vehicle diagnostics/programming which is called TechLine Connect. I just wanted to explain what that was. I would expect most Snap-On or Autel scanners to be able to do the relearn.
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Thanks i appreciate your time and knowledge and you explained that simple enough that i even made sense of it lol.I find that sometimes people on sites like these talk in a language that only experienced builders understand and someone like me is scratching me head.I will try this tomorrow and post the results and thanks again.
Thats cool, should be a nice runner. FIL has a '14 Sierra and I'm shocked it's past 100k with OE trans, motor and AFM lifters all still operating. And 25k Amsoil changes.Yeah it’s a mild cam i just put the L8T in so basically stock as i didn’t want to get into a tuning problem.People here tend to get tuning done away from here and i’m not smart enough to buy a tuner and then do any programming with it.
No problem and you're welcome. More than happy to explain and dig into the "what's what". Because I've been there. Especially when learning a new subset of fixing something or a unique repair. Long story short, swapped an LQ4 into a 5.3 Tahoe, mild cam. Similar situation P0300 and blinking CEL with above 2k RPMs. Learned about the CKP procedure after that. Also learned that misfire detection in the PCM contributes to it staying in torque converter lockup or it locking and unlocking frequently. But fortunately there have been some very gracious folks online here and there that have been saints in taking the time and sharing the little things.Thanks i appreciate your time and knowledge and you explained that simple enough that i even made sense of it lol.I find that sometimes people on sites like these talk in a language that only experienced builders understand and someone like me is scratching me head.I will try this tomorrow and post the results and thanks again.
I still find forums the best for figuring out the technical things. Facebook has turned into a whole ego-fest and a lot of just nasty folks. It's a shame because the reach of Facebook is phemonional.
Out of curiosity what does this crank relearn do?Does it fine tune the computer so it knows exactly where tdc is for timing purposes with the vvt and ignition timing or am i way off base?I have a low mileage Lbz silverado that my son wrecked a few years ago and i’m building it back for myself and it’s going to be my summer truck.I used do bodywork for a living 25 years ago and it’s surprising how much the skillset stays with you although the paint products sure have changed.
This motor broke valve springs twice in 160000 km so they got updated just for insurance as i don’t know if they were original or not?They had a green stripe but i couldn’t find much out about them.When i put the heads on the bench you could push on the springs and they didn’t have the same pressures so i wasn’t chancing it.The motor that was in this before disintegrated number 8 hole and blew the head all to crap.Funny this motor broke the 8 spring also before and you can see where the head and piston had marks but the cylinder looked good and tested good with my leak down tester.Thats cool, should be a nice runner. FIL has a '14 Sierra and I'm shocked it's past 100k with OE trans, motor and AFM lifters all still operating. And 25k Amsoil changes.
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