2013 Yukon Denali Hybrid AFM Delete won't pass emissions

tell the tuner if he's using hpt tuners to license the tune, and then change the drop down box for afm from whatever it is to what it's not now.. reflash the truck and go test drive it. what is in the box doesn't matter, just change it to the other thing. depending on the version of hptuners he has on his laptop, some have reportered it as labeled incorrectly at first and fixed in later updates. as in sometimes the factory tune shows disabled(while it's actually working) for other people it shows enabled. it doesn't matter, just change it to the other one and save. it will disable it.

good luck.

everyone sees hybrid and freaks out. its annoying

j91z28d1 said:

hptuners will disable afm and all monitors will set.

I have done it on my 2011. so don't listen to anyone that says a hybrid can't be done.

worse case you buy hptuners, 2 credits. change one drop down box and then sell hpt if you don't need it. or find a local that has it and willing to do it for you.


curious thou, did you change the cam or just drop in 16 new non afm lifters on top of the old cam? did you replace the vlom with a non afm flat one? I only ask cause usually guys that try dropping in new lifter on the afm cam have a missfire and guys that do a delete kit which is cam, lifter and top plate. the truck runs like crap with just dongle turning it off.

Click to expand...

Hi! I found a local guy who tuned it and all is perfect now!

We did not change the cam and we did put non afm lifters on it.
Ive been driving it for about 1.5 years with zero issues.
My gas mileage has gone down about 2mpg but other than that its just fine.
The lifter collapsed with about 87,000 miles on it and In just about to turn 100,000.

HybridYukon13 said:

Hi! I found a local guy who tuned it and all is perfect now!

We did not change the cam and we did put non afm lifters on it.
Ive been driving it for about 1.5 years with zero issues.
My gas mileage has gone down about 2mpg but other than that its just fine.
The lifter collapsed with about 87,000 miles on it and In just about to turn 100,000.

Click to expand...

Is your tuner's secret sauce so secret,
that not only will you not give us any clue what your tuner did,
but you also won't tell us his (business) name?

HybridYukon13 said:

Hi! I found a local guy who tuned it and all is perfect now!

We did not change the cam and we did put non afm lifters on it.
Ive been driving it for about 1.5 years with zero issues.
My gas mileage has gone down about 2mpg but other than that its just fine.
The lifter collapsed with about 87,000 miles on it and In just about to turn 100,000.

Click to expand...

that's awesome. there's been a few people try putting non afm lifters on a afm cam and they seem to always have bad results. like missing and running badly. that's awesome that it worked for you.

thanks for the update.


now I have even more questions lol. I wonder if the hybrid cam being different grind allows for the lifter change on the oem cam. huh.

Marky Dissod said:

Is your tuner's secret sauce so secret,
that not only will you not give us any clue what your tuner did,
but you also won't tell us his (business) name?

Click to expand...

never said it was a secret...he tuned it with his computer program.....took about 20 minutes

Ok, so, the details of his tune are a secret, and he is a secret ...
got it.

Marky Dissod said:

Ok, so, the details of his tune are a secret, and he is a secret ...
got it.

Click to expand...

what exactly are you asking him?
dude went to a shop and they changed one drop down box under afm. wrote that to the ecm and he drove away? I doubt he knows or cares what the tech's name was or what software he used. 99% chance it was hptuners.

For example:
my tuner was (and is) pcmperformance.com.
On my 2013 YXL, he:
addressed the spark timing tables for crisper throttle response, power, MpGs
reduced DFCO spark timing so it would coast 'lighter' and longer than GM's setting in upper gears
raised the WOT Upshift & Downshift RpM thresholds
made the 'Normal' Up & Down Shift Points table more enthusiastic, especially over 37% TPS
made the 'Tow/Haul' Shift Points table Tow-ier / Haul-ier
improved powertrain braking in lower gears

*accommodated my special request
INCREASED the V4 mode duty cycle and availability at lower speeds / gears
so I could putt around gently in metro/urban stop'n'go using more V4 mode than GM originally intended
*after a few years of mildly improved city MpGs, this eventually caused increased oil consumption
I will never do this again.
*What I might try in the future (?) - instead of disabling the V4 mode flag -
raising the V4 mode enable coolant temp threshold to 221F,
so that V4 mode only ever activates if the engine is running hot enough
that it might be in danger of overheating; might buy another 5min

But if he doesn't think his tuner deserves a recommendation here on this forum,
so others can appreciate the benefits, like I said, got it.

dude it's a hybrid, this is a hybrid sub forum. literally none of that can be tuned.

hptuners has a small hand full of things defined for the 67A ecm. you can't even adjust Maf fueling vs Hz. which is the the very base of any fuel tuning. you can change the PE target fueling but it's a hybrid, who dynos a hybrid and tunes wot? it can't even identify the hybrid transmission controller, it's some one off maybe Allison based hardware, then custom software written for it by gm, dodge, BMW and can't remember but maybe Mercedes collaboration. they started with a Allison hybrid bus transmission and scaled it down to a passenger vehicle. there's a fwd version too.

I'm telling you exactly what he did. he licensed the tune, changed one drop down box. wrote back to vehicle and droveit back around front for him. which is exactly what he asked for and wanted, just make it mass the emissions monitors

These don't have a torque converter to adjust lock up. there is no tow haul mode, as there is no over drive. it's a 4 speed tranny with 4th being 1:1. any over driven gear ratios are completely electric motors inside the tranny driven.