RepairPal Certified shops can diagnose and repair your 2007 Chevrolet Trailblazer. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Sorry to say, you need diagnostic help. Chasing this code without a professional scan tool is very limited. You can check the circuits for speed sensing for the radio, gauge cluster, etc, but you would really be taking a shot in the dark.