This TSB applies to 2007 GM vehicles equipped with the Vortec Gen IV 6.0L V8 engine and Hydra-matic 4L60-E or 4L70-E transmissions. Models include Chevy Avalanche, Silverado, Suburban and Tahoe, and GMC Sierra, Yukon and Yukon XL.
Some customers may comment on a surge or hesitation during an active fuel management system deactivation transition point (although they will simply complain about a surge or hesitation).
Before reprogramming the ECM and TCM, compare the vehicle to a like vehicle. This may be a normal condition for an active fuel management system equipped vehicle. The vehicle you are evaluating may be a little harsh in AFM transition. A calibration update was released for the ECM and TCM to soften the feel of the AFM transition.
ECM: New calibration to address customer concern of bump during AFM transition. Must also program the TCM with the latest calibration.
TCM: New operating system and calibrations to improve engine performance and shift quality. You must also program the ECM with the latest calibrations.
Updated ECM and TCM calibrations are now available to address this concern.