Service Update for Inventory Vehicles Only-Cold Start P1400 On-Board Diagnostic (OBD) System Improvement-Reprogram ECM-Expires June 30, 2008

THIS SERVICE UPDATE INVOLVES VEHICLES IN CERTAIN DEALER INVENTORY ONLY AND WILL EXPIRE JUNE 30, 2008.

This bulletin provides a service procedure to reprogram the Engine Control Module (ECM) calibration on certain 2008 Cadillac Escalade; GMC Sierra, Yukon, Yukon XL; and HUMMER H2 vehicles, equipped with a 6.2L V8 (RPO L92 - VIN 8) engine. The revised calibration corrects a Service Engine Soon (SES) light for DTC P1400 after a cold start. To verify if an updated calibration is required, refer to the following procedure in this bulletin.

This service procedure should be completed on involved vehicles currently in dealership inventory as soon as possible, but no later than June 30, 2008, at which time this bulletin will expire.

A list 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.

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 the Techline Information System (TIS) 2000 terminal with the calibration update. Use data version 12.0 for 2007 or later, available on TIS 2 Web November 26, 2007 ; and on TIS DVD version 12.0/ 2007 or later, mailed to dealers beginning December 5, 2007. If you cannot access the calibration, call the Techline Customer Support Center and it will be provided.

GMVIS must be checked to determine if a specific vehicle requires this action. If the system indicates that Service Update Bulletin 07338 remains ‘open’ and ECM reprogramming has not taken place, reprogram the ECM using a Tech 2® scan tool with the calibration update from TIS 2 Web.

Tech 2 Pass-Thru Method for the Engine Control Module (ECM)

Notice: Before reprogramming, please check the battery condition to prevent a reprogramming error of any of the modules due to battery discharge. Battery voltage must be between 12 and 16 volts during reprogramming. If the vehicle battery is not fully charged, use jumper cables from an additional battery. Be sure to turn off or disable any system that may put a load on the battery, such as automatic headlamps, daytime running lights, interior lights, heating, ventilation, and air conditioning (HVAC) system, radio, engine cooling fan, etc. A programming failure or control module damage may occur if battery voltage guidelines are not observed.

The ignition switch must be in the proper position. The Tech 2® prompts you to turn ON the ignition, with the engine OFF. DO NOT change the position of the ignition switch during the programming procedure, unless instructed to do so.

Make certain all tool connections are secure, including the following components and circuits:

DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

DO NOT turn OFF the ignition if the programming procedure is interrupted or unsuccessful. Ensure that all control module and DLC connections are secure and the Tech 2® operating software is up to date.

1. Verify that there is a battery charge of 12 to 16 volts. The battery must be able to maintain a charge during programming. Use an additional jump battery, if necessary. Only use approved Midtronics charger or Jumper Packs, etc. to maintain proper battery voltage during programming.
2. Reprogram the engine control module (ECM). Refer to SI and Service Programming System (SPS) documentation for ECM programming instructions, if required.

For vehicles repaired under this service update, use: