pkincy

I was missing what was checked (old man's memory), but it is the CVN number in the software. Any bit that is changed will change that number. But yes, some handhelds will keep the CVN number unchanged.

Take a car in for warranty work and they hook up to the ALDL and if the CVN number is wrong they add a block to your warranty and give you a call and tell you the work will be on your account not GMs.

MerakiAutoworks

Tune.. Lots of other things are fine!

-Josh

CONMAX

i am an electronics development engineer with 20 yrs developing firmware for embedded systems. if i did have a major drivetrain failure if the car was under warranty, i would quickly install the stock tune, update the reflash counter to match the factory numbers, and remove all bolts on like CAI's.

now tell me how the dealer or factory techs could tell the car ever had a tune?

pkincy

You are definitely not a good Electronic Developments engineer if you can't figure out that GM could both note the number of times the pcm has been flashed and have a check on what was flashed.

You also have not read this whole thread. It takes them about 30 seconds to match the CVIN numbers (or not match them) from all tunes that have been in the car. Admittedly there are a few tuning devices (did I mention Diablo) that can spoof the CVIN number so that it doesn't show as a "tuned" flash. However the major tuning software companies no longer spoof the CVIN number.

Higgs Boson

try it out and let us know your results. something you can get done over the weekend I am sure.

BTW, in reality, when your engine blows on the highway and you call a tow truck and it takes your car to the nearest chevrolet dealer, good luck removing parts and rewriting code. that's the scenario for 99% of people, not many tows to the Hooli Hot Rod House.

CONMAX

of course if you engine blows and you have it towed to the dealer with the tune still installed, you won't be covered. usually, you can get it towed home or bring your laptop to the scene and download the stock tune. using a microcomputer emulator to access non user firmware, the # of reflash instances can be changed. i always record this number and change it to match the value before it was tuned. GM has even made this easier for us by allowing access to the serial debug port through a 2 pin connector. a simple rs232 driver is all that is needed from a laptop to access the base address where this data is contained.

this still may be beyond the average hobbyist or tuner's ability, but it is really very basic for any firmware engineer with some hardware knowledge.

Higgs Boson

video it and show us. also, are you going to fly out to help people with their cars? or is your post not really for the benefit of the community?

pkincy

Is the CVN number kept separately or only kept for the tune that is actually in the car when the dealer pulls it? If the CVN number can be spoofed (and it is possible but the major tuning software vendors don't spoof it any longer) or is only available for the currently installed tune and you can reduce the # of flashes without leaving bread crumbs then maybe you have a workaround. However if the # of flashes and/or the past CVN numbers are available to GM than you are toast.

I quit tuning when GM (and others) made the determination that any tune other than stock would block the warranty.

Just did a quick check on CVN (Calibration Verification Number) and 10 are stored in memory. So the last 10 tunes CVNs are readily available to GM. And reloading your stock tune 10 times won't cover up the nonstock tunes as the CVN history is only changed if the tune's CVN is different.

So if your ecm has 10 or over legal stock tunes and you had access to all of them and then loaded each one once you would change the CVN history to a set of 10 numbers that would match stock tunes. Lacking that you are out of luck.

pkincy

Now this is ancient information and was issued when checking CVN data was in its infancy (mid 08) but this was the GM process. Back in those days Ford did check the # of flashes but GM never used that data as a test for non stock tunes.

Quote:
#PIP4386: Identifying Aftermarket Engine Calibrations - (Apr 8, 2008)


Subject: Identifying Aftermarket Engine Calibrations


Models: 2005-2009 GM Passenger Cars and Light Duty Trucks

except Pontiac Vibe, Chevy Aveo, and All Saab Models




------------------------- ------------------------- ------------------------- -


The following diagnosis might be helpful if the vehicle exhibits the
symptom(s) described in this PI.



Condition/Concern:
A dealer may have the need to verify engine calibrations. If a dealer feels an aftermarket power-up calibration has induced engine and/or drive train damage, there is now a way to verify what calibration is currently in the vehicle.
If a suspicious hard part failure is observed in the engine, transmission,
transfer case, or driveline, perform the calibration verification described
to determine if a non GM issued engine calibration is installed. Non GM
issued engine calibrations subject driveline components to stresses
different than those that these components were validated to. Repairs to
transmission, transfer case and / or other driveline components where a non GM engine calibration has been verified, are not covered under the terms of the New Vehicle Warranty.

Recommendation/Instructio ns:
Instructions for confirming Calibration Verification Number (CVN)
• Go to TIS2WEB

• Select Calibration Information (SPS Info)

• Enter VIN

• Select "Get Cal ID"

• Select ECM Engine Control Module

• Hit "next"

• Select "Complete History"

• Print

Take Printout to Vehicle along with Tech II
• Plug in Tech II

• Go to diagnostics and build the vehicle

• Select Powertrain

• Select the engine

• Select F0 - Engine Control Module

• Select F4/F5 - I/M information System / Module ID information*

• Select F1

• Compare the calibration ID and Calibration Verification Numbers
(CVN) to the Calibration Verification Numbers (CVN) on the printout.

* This step may vary by controller; use the Module ID Information in the
Engine Controls.

Although the part numbers will be the same for each, it's the CVN that will
determine if the calibration is GM issued.

If ALL of the CVN's are EXACTLY the same, the calibration is GM issued.

If the part numbers match and ANY calibration verification numbers (CVN's) do not match the printout, it is likely that a non GM certified calibration has been installed.

In order to document the case - a CLEAR digital picture should be taken of
the TECH 2 screen showing the VIN and the CVN's that do not match the
TIS2WEB printout. The picture and a PDF copy of the TIS2WEB printout should be forwarded to jay.dankovich@GM.com for verification along with the VIN and the reason the vehicle is currently in for service. Please copy your GM Area Service Manager (DVM/DSM) on the e-mail. GM will verify if the CVN's are not GM issued and respond via e-mail within 48 hours.

If both the Part numbers and the CVN are different, photograph the part
numbers and CVN's on the tech 2 screen as described above, assuring the VIN shows clearly in the photograph of the TECH2 screen, and check to see if the vehicle has the latest released calibration. If the latest released calibration is not installed in the vehicle, the part numbers will not match, and the CVN's won't either. E- mail the original Part Numbers and CVN's found in the vehicle on the TECH 2 to: jay.dankovich@GM.com to check if the calibration and CVN matches a previous release. Recalibrate with the latest released cal and re-check against the part numbers and CVN's that are released.


Please follow this diagnostic or repair process thoroughly and complete eachstep. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

davepl

Please explain in detail so that a knowledgeable enthusiast can follow along.

I've got an ELM327 chip and an RS-232 cable.

I've got a ton of OBD2 interfaces.

I have HPTuners.

Tell me how to access the flash count with any of those, I'll be impressed!

vettefordays

LOOOOOOOOOOOOOOOOL

hotmotorsports

That is a good price, but for $3,000, I don't want it to be "basically" the same as the GMEPP, I want it to be the same. I got 84 Mos, 100,000 miles GMEPP for $2,500 on my new Grand Sport.

Chuck M

trevor90

[QUOTE=Warp Factor;1594654464]Sorry, but that's a little naive. Auto companies can present "expert" witnesses who may be willing to testify that the increased heat from an aftermarket exhaust or turbo overheated the window motor. It will be up to you to counter or disprove those claims. You can battle it out in court, but the high likelihood is that your resources will will run out before theirs will, or that your litigation expenses will far exceed the cost of your claim.



uh, you have to be kidding right? im sure you certainly in no way believe that.. if you do, you probably never need to use the internet.

Mikec7z

while there are cvn numbers and other things that may be able to be changed back to try to hide the tune....

Couldnt GM just go through the car's history and say... "alright, you went from pulling 11lbs of boost here... to 15lbs here for x amount of time.... and then back to 11lbs here.... amazing how magical your car is huh?!"

TKgs2010

I have a few "tweaks" on my new ZO6, all good with the Tech and Service Manager.

Mikec7z

For some things, yeah, but no matter how cool or nice you are, if you have an aftermarket tune, and something goes wrong with your engine or trans, GM is going to void your warranty when they find the AM tune, and unfortunately, the dealers cant hide it from GM to the best of my understanding.

robertbruce

Leave it stock or you are f*^#+d.

hotmotorsports

Yeah until the Area GM Rep just happens to be there when you have an issue and directs voiding the warranty coverage. I've seen it... AND reprimands the Dealership. That actually happened at a Dealership I worked at a while back.

Scoobydoobydoo

I agree and the other thing I dont understand is why someone would risk voiding their warranty for a bolt on that may only add 20 h.p. on a car with 650h.p. from the factory. Is that extra 20 going to really make a difference ?

Thomasmoto

I actually witnessed this very thing happen a few years back on a brand new Grand Sport that had an Edlebrock blower on it. He made a huge deal about it and boasted enough for the whole shop to hear him.