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Did the dealer leave my TCM unlocked??

emeryz28

By emeryz28
in Engines & Drivetrain

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emeryz28 Enthusiast

emeryz28

Posted
Posted

Is this even possible?

 

2015 Silverado Z71 crew cab LTZ 6.2 8 speed

 

I have a diablo i2 and usually run the 91 octane tune with the throttle boost, tire size correction and DOD turned off.    I have put this tune in there a few times, as I set it back to stock when it goes to the dealer. Every time it tells me that it cannot read the TCM or it is "not supported" and it does not give me any trans options.

 

Most recently it was at the dealer for the delayed transmission engagement. The truck would delay then shift hard and audibly from R-D in the morning, especially when it was cold.  They replaced some clutch packs, solenoids, I believe the stator shaft, did a flush and a retune and fixed the problem.  It has been about 3 week so I just got around to putting in the Diablo tune again,throttle boost, tire size correction and DOD turned off.  This time it did not alert me about the TCM and it is asking me if I want to increase shift firmness and RPM, for all 1-8 shifts.  I am fairly certain I have not updated the tuner lately to reflect any new adjustments diablo made available.

 

So my question is, when the dealer was in there tuning stuff, did they somehow leave the TCM open or unlocked for me to now access and adjust parameters?

 

thanks 

tbarn Senior Enthusiast

tbarn

Posted
Posted

The dealer can't "tune" anything. Relearn shift  pattern is all. Even that is mostly automatic via GDS or TIS.

Mileguru Enthusiast

Mileguru

Posted
Posted

I'm not sure how the Diablo handheld works, but with an AutoCal or HP Tuners, the 2015 8-speed TCMs have always been able to be tuned. The only TCM that can't be tuned without paying HP Tuners to unlock it (or using Trifecta) is the T87A in the 2017+ models. 2014 - 2016 uses the T87.

TJay74 Senior Enthusiast

TJay74

Posted
Posted
31 minutes ago, tbarn said:

The dealer can't "tune" anything. Relearn shift  pattern is all. Even that is mostly automatic via GDS or TIS.

 

 

Huh??? The dealer most certainly "tune" modules in the sense that when GM had them flash a firmware into the OP's TCM at that point the dealer was tuning the TCM. GM does revise calibrations based on issues and then has those calibrations flashed when work is done.

Mileguru Enthusiast

Mileguru

Posted
Posted
59 minutes ago, TJay74 said:

 

 

Huh??? The dealer most certainly CAN/DOES "tune" modules in the sense that when GM had them flash a firmware into the OP's TCM at that point the dealer was tuning the TCM. GM does revise calibrations based on issues and then has those calibrations flashed when work is done.

This is true. It does not happen often, but it is true.

 

P.S. I edited TJay74's post with "CAN/DOES"

L86 All Terrain Senior Enthusiast

L86 All Terrain

Posted
Posted

I don't think the dealer can "tune" any of these things? I could be wrong, but I was under the impression that they only can load canned GM tunes up, not alter or make changes to said tune. Otherwise, every dealer would have to have someone extremely knowledgeable in tuning software and how to change and alter fuel/air ratios and ignition timing without grenading the engine. Seeing as how most dealers only have 1 "diesel guy" I doubt they all have a professional tuner in house. They can flash, and install new tunes, can they create and alter the tunes? Doubtful as GM wouldn't want techs putting in hot tunes on the sly for their buddy's warrantied truck. It seems weird that new parameters are available to you without updating your Diablo programmer. At least it is a good problem to have on your end!  

Mileguru Enthusiast

Mileguru

Posted
Posted
12 hours ago, 10SierraA.T. said:

I don't think the dealer can "tune" any of these things? I could be wrong, but I was under the impression that they only can load canned GM tunes up, not alter or make changes to said tune. Otherwise, every dealer would have to have someone extremely knowledgeable in tuning software and how to change and alter fuel/air ratios and ignition timing without grenading the engine. Seeing as how most dealers only have 1 "diesel guy" I doubt they all have a professional tuner in house. They can flash, and install new tunes, can they create and alter the tunes? Doubtful as GM wouldn't want techs putting in hot tunes on the sly for their buddy's warrantied truck. It seems weird that new parameters are available to you without updating your Diablo programmer. At least it is a good problem to have on your end!  

TJay74 and I weren't saying that the dealer had a "tuner" on site altering the tune. We were just saying that the semantics of the word "tune" does allow one to say that loading a new GM canned tune to a TCM means that they are technically "tuning" the transmission. But no, no one at a dealership is altering shift points and pressures or anything.

emeryz28 Enthusiast

emeryz28

Posted
  • Author
Posted

thanks for the responses. I am just confused on why shift points and pressures were all of a sudden available on my diablo when for the past 3 years it said the TCM was unable to be read.  

tbarn Senior Enthusiast

tbarn

Posted
Posted
On 8/1/2018 at 9:06 PM, TJay74 said:

 

 

Huh??? The dealer most certainly "tune" modules in the sense that when GM had them flash a firmware into the OP's TCM at that point the dealer was tuning the TCM. GM does revise calibrations based on issues and then has those calibrations flashed when work is done.

That would be a very broad interpitation of the general meaning of "tune".

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