Service Update for Inventory and Customer Vehicles-E85 Virtual Flex Fuel Sensor (VFFS) Update-Reprogram ECM

THIS BULLETIN HAS BEEN REVISED TO ADD 2007 CHEVROLET EXPRESS AND GMC SAVANA VANS TO THE LIST OF INVOLVED VEHICLES.

PLEASE DISCARD ALL COPIES OF BULLETIN 06162B, ISSUED JUNE 2007.

THIS SERVICE UPDATE INCLUDES VEHICLES IN DEALER INVENTORY AND CUSTOMER VEHICLES THAT RETURN TO THE DEALERSHIP FOR ANY REASON, AND WILL EXPIRE AT THE END OF THE INVOLVED VEHICLE'S 8 YEAR/80,000 MILES (130,000 KM) EMISSION CONTROLLER WARRANTY PERIOD.

This bulletin provides a service procedure to reprogram the Engine Control Module (ECM) on certain 2006 Chevrolet Impala, Monte Carlo, Silverado, Avalanche, Tahoe, Suburban; GMC Sierra, Yukon, Yukon XL; 2007 Buick Terraza; Chevrolet Impala, Monte Carlo, Uplander, Silverado Classic, Tahoe, Suburban, Avalanche, Silverado, Express; GMC Sierra Classic Yukon, Yukon XL, Sierra, Savana; and Pontiac Montana SV6 vehicles, equipped with E85 compatible 5.3L V8 (RPO L59 - VIN Z, RPO LC9 - VIN 3 or RPO LMG - VIN 0); 3.5L V6 (RPO LZE - VIN K); or 3.9L V6 (RPO LGD - VIN W) engines. This reprogramming will update the Virtual Flex Fuel Sensor (VFFS) software algorithm installed in these E85 compatible vehicles to better adapt to the wide variety of ethanol concentrations and refueling processes they may encounter.

This service procedure should be completed as soon as possible on involved vehicles currently in dealer inventory and customer vehicles that return to the dealer for any type of service during the 8 year / 80,000 mile (130,000 km) Emission Controller Warranty.

A ist of involved vehicles currently in dealer inventory is available on the "Service Update Bulletin Information" link under the "Service" tab in DealerWorld (US), or attached to the Dealer Communication (Canada), used to release this bulletin. Customer vehicles that return for service, for any reason, and are still covered under the vehicle's emission warranty, and are within the VIN breakpoints provided beleow, should be checked for vehicle eligibility in the appropriate system listed below:

Important: Dealers are to confirm vehicle eligibility prior to beginning repairs by using the GM Vehicle Inquiry System (GMVIS). Not all vehicles within the above breakpoints may be involved.

Do not attempt to order the calibration number from GMSPO. The calibration numbers required for this service procedure are programmed into control modules via a Techline Tech 2® scan tool and TIS2Web website with the following calibration updates..

If you cannot access the calibration, call the Techline Customer Support Center and it will be provided.

The "Required Field Actions" section of the GM Vehicle Inquiry System (GMVIS) must be checked to determine if a specific vehicle requires this action. If GMVIS indicates that Service Update Bulletin 06162C remains ‘open’ and ECM reprogramming has not taken place, reprogram the ECM using a Tech 2 scan tool with the calibration update from TIS2Web.

Refer to the latest version of Technical Service Bulletin 06-06-04-010 and Service Information to perform the ECM Reprogramming procedure and, if needed, the Fuel Composition Reset Procedure. The Fuel Composition Reset Procedure is only needed if the measured ethanol content is more than 15% different than the ECM estimated value.

Important: If it is assured that only non-blended (containing 10% or less ethanol) gasoline is in the vehicle fuel tank, proceed directly to ECM programming.

For vehicles repaired under this product enhancement, use: