GM bump start
This TSB applies to 2007-2013 Chevy Avalanche, Silverado, Suburban and Tahoe, GMC Sierra and Yukon, and Cadillac Escalade vehicles. These vehicles have a computer-controlled cranking system, or CCCS (also called Bump Start). If the ignition key is turned to the START position, and then released when the engine begins cranking, the engine will continue to crank for a few seconds or until the engine starts. Some owners may comment that this feature is inoperative.
When the Low Fuel warning lamp is on and/or the FUEL LOW message is displayed in the driver information center, the CCCS will be disabled. This is normal operation and no repairs should be made. Ask the owner to add fuel and re-check the bump start operation.