Product Enhancement for Inventory Vehicles Only-Transmission Control Module (TCM) Electrical Contact Notice Label-Expires on September 30, 2006

This bulletin provides a service procedure to apply a notice label on the engine radiator air upper baffle on certain 2006 Chevrolet Silverado and GMC Sierra model vehicles, equipped with a 6.6 L V8 (RPO LLY - VIN 2 or RPO LBZ - VIN D) Diesel or 8.1L V8 (RPO L18 - VIN G) gasoline engine; and an Allison 1000 (RPO MW7) automatic transmission currently in dealer inventory. The Transmission Control Module (TCM), which is located under the hood on the driver side upper fan shroud, is near the battery positive access terminal on the engine. If jumper cables or any other wiring that is carrying battery positive voltage contacts the TCM housing, excessive current can flow through the TCM. This may damage the TCM module and cause a potential no-start condition.

To alert anyone working on these vehicles to avoid electrical contact with the TCM, Dealers are to place this notice label under the hood at the location noted in the service procedure.

This service procedure should be completed as soon as possible on involved vehicles currently in dealer inventory, but no later than September 30, 2006, at which time this bulletin will expire.

A list of involved vehicles currently in dealer inventory is attached to the Administrative Message (GM), Dealer Communication (Canada), used to release this bulletin.

Important: Dealers are to confirm vehicle eligibility prior to beginning repairs by using GM Vehicle Inquiry System (GMVIS).

An initial supply of TCM Notice Labels required to complete this Product Enhancement will be pre-shipped to involved dealers of record. This pre-shipment is scheduled to begin the week of June 26, 2006 (U.S.); July 3, 2006 (Canada) and will be approximately 100% of each dealer’s vehicle inventory.

If additional labels are required:

For US : US dealers should contact the DWD Store at 1-866-700-0001; or through the DealerWorld website at www.gmdealerworld.com, then click on the DWD Store link. Be sure to request label for Product Enhancement 06521. DO NOT ORDER THIS PART FROM GMSPO.

For Canada: Canadian dealers should contact GM Canada's WINS Call Centre by sending a fax with your request to 1-888-888-4622. Be sure to request label for Product Enhancement 06521. DO NOT ORDER THIS PART FROM GMSPO.

Label Installation Procedure

1. Open the hood.

Figure 1 (Front of Vehicle)




2. Locate the available label surface area on the engine radiator air upper baffle on the driver side (1) in front of the Transmission Control Module (TCM) (2). The TCM is located approximately 7 inches (175  mm) from the positive access terminal (3). (Figure 1).
3. Clean dirt, oil, etc. from this located engine radiator air upper baffle area.
4. Remove the backing from the new label and apply the new label to the cleaned area on the engine radiator air upper baffle, so that the label is readable when the hood is raised. (Figure 1).

Notice:  Do not attempt to remove or loosen the new label once it has been applied, as this will deface the label.

5. Beginning at the center of the label and using a clean, dry cloth, smooth and secure the new label. Any air bubbles can be removed by puncturing with a pin and smoothing with the cloth.

For vehicles repaired under this product enhancement, use: