[Klaus]

Non-GM Engine Calibrations

General Motors does not endorse the use of aftermarket (non-GM issued) engine calibrations in any of its gasoline or diesel powered vehicles in North America. When non-GM issued engine control calibrations are detected, steps should be taken to void the Powertrain portion of the New Vehicle Warranty.

Bulletins 08-06-04-006A (diesel engine vehicles) and 08-06-04-033 (gasoline engine vehicles) outline the procedures to be used in identifying the presence of non-GM issued calibrations. Non-GM issued engine calibrations subject driveline components to stresses different from the calibrations to which these components were validated. The stresses resulting from the non-GM calibrations and equipment were not validated by GM and therefore cannot be warranted on any components that are subject to those stresses.

Where a non-GM engine calibration has been verified, current and future repairs to engine, transmission, transfer case, driveline, axle and/or other driveline components are not covered under the terms of the New Vehicle Warranty.

GM TechLink August 2008