I just noticed a GM Techlink article telling the GM Dealer mechanics to look for Engine Control Module or Transmission Control Module calibration modifications (Aftermarket Tuners-Bullydog/Diablosport/performance chip/Superchips/Hypertech/Jet etc), and if found, to not cover internal engine or transmission component failures. So you are warned if your contemplating or have used an aftermarket tuner. I know some tuners can reverse the calibrations to factor, but apparently there is some sort of history log and they can tell if the OEM calibrations have been restored. If you have tuned your ECM or TCM it sounds like you may be screwed unless your shop doesn't check.
FWIW I didn't see any mileage or performance boost from the last tuner I bought (Diablosport), but I didn't replace the exhaust headers or intake other than a CAI.
See full tech link article here: http://sandyblogs.com/techlink/?p=4248
Quote: "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."
FWIW I didn't see any mileage or performance boost from the last tuner I bought (Diablosport), but I didn't replace the exhaust headers or intake other than a CAI.
See full tech link article here: http://sandyblogs.com/techlink/?p=4248
Quote: "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."
