There is a new recall for the ignition lock on some 2011-2012 Avalanches built between MAY 17, 2011 - AUG 04, 2011. The recall also covers other 2011-2012 GMT900 models.
http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM470007/RCLRPT-14V827-0535.PDF
The problem is that the ignition switch could get stuck in the start position when the interior is hot.
http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM470007/RCLRPT-14V827-0535.PDF
The problem is that the ignition switch could get stuck in the start position when the interior is hot.