http://sandyblogs.com/techlink/?p=4248
Found this on TechLink
February 5, 2015
When alterations to GM engine or transmission control module calibrations are made by owners, it may subject powertrain and driveline components (the engine, transmission, transfer case, driveshaft and rear axle) to stresses that were not tested by GM. These unknown stresses have the potential to alter reliability, durability and emissions performance. GM is identifying an increasing number of engine, transmission and catalytic converter part failures due to non-GM aftermarket calibrations.
As a result, GM has adopted a policy that prevents any unauthorized warranty transaction submissions to any remaining warranty coverage to the powertrain and driveline components whenever the presence of a non-GM calibration is confirmed, even if the non-GM control module calibration is subsequently removed.
TIP: GM requires retrieving the calibration information and performing the calibration verification procedure whenever a hard part failure may have occurred on internal engine components before disassembly, repair or replacement of an engine assembly under warranty. It is also strongly recommended that the calibration verification procedure be performed whenever diagnostics indicate that transmission, transfer case, rear axle or catalytic converter replacement is needed.
If a non-GM calibration is found and verification has taken place through GM, the remaining powertrain and driveline warranty may be blocked and notated in Global Warranty Management (GWM) and the dealership will be notified. This block prevents any unauthorized warranty claim submission.
Found this on TechLink
February 5, 2015
When alterations to GM engine or transmission control module calibrations are made by owners, it may subject powertrain and driveline components (the engine, transmission, transfer case, driveshaft and rear axle) to stresses that were not tested by GM. These unknown stresses have the potential to alter reliability, durability and emissions performance. GM is identifying an increasing number of engine, transmission and catalytic converter part failures due to non-GM aftermarket calibrations.
As a result, GM has adopted a policy that prevents any unauthorized warranty transaction submissions to any remaining warranty coverage to the powertrain and driveline components whenever the presence of a non-GM calibration is confirmed, even if the non-GM control module calibration is subsequently removed.
TIP: GM requires retrieving the calibration information and performing the calibration verification procedure whenever a hard part failure may have occurred on internal engine components before disassembly, repair or replacement of an engine assembly under warranty. It is also strongly recommended that the calibration verification procedure be performed whenever diagnostics indicate that transmission, transfer case, rear axle or catalytic converter replacement is needed.
If a non-GM calibration is found and verification has taken place through GM, the remaining powertrain and driveline warranty may be blocked and notated in Global Warranty Management (GWM) and the dealership will be notified. This block prevents any unauthorized warranty claim submission.