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info on GM'S crackdown on aftermarket tunes...


Well-known member
Feb 26, 2005
queensbury,new york
the following is the p.i for calibration confirmation from GM


#PIP4386: Identifying Aftermarket Engine Calibrations - 2.0 2.2 2.4 2.8 2.9 3.0 3.1 3.2 3.4 3.5 3.6 3.8 3.9 4.2 4.3 4.4 4.6 4.8 5.0 5.3 5.7 6.0 6.2 7.0 7.4 8.1 - (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.

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.

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 each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
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Today, 12:20 PM #2 FortMorganAl
CF Senior Member

Member Since: Feb 2007
Location: Currently somewhere in IL,IN,KY,TN,MS,AL, or FL


Be careful out there!!:bash
And this is wrong because we can find out if a customer has a custom tune?
And I would love to know who is putting PIs on the web.
Allthebest, c4c5
And this is wrong because we can find out if a customer has a custom tune?
And I would love to know who is putting PIs on the web.
Allthebest, c4c5
;shrug Didn't say it was wrong,right or indifferent.Just posting that GM will be denying warranty claims if they find an aftermarket tune.Lighten up!
HI there,
No, thats not entirely accurate.
GM has been evaluating issues caused by these aftermarket tunes.
If you look at Callaways calibrations, they can be classified as aftermarket, yet do not harm engine internals.
There are many grey areas to these PIs.
This is the reason why I said above, because interpretation is vague in certain points.
I, professionally, can assist my customers better by understanding the aftermarket tune more and in turn, serving Corvette customers correctly.
Allthebest, c4c5
I would have to agree that if there is a failure, the calibration check could help pinpoint why. ;shrug

Now if GM has/had directed their technicians to solely look for mis-mathes in a witch hunt, that is BS and unless the tune itself cause the component failure, consumers do have rights under various laws. But the original poster, might not have read into this far enough ;)

Ohhh, and Hi Jessie :w

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