Diagnostic Aids
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
A defective fuel level sensor most likely will not set DTC P0463. The sensor has a 500 ohm default resistor that will prevent it from meeting the code setting criteria of this DTC. Look for problems in the wiring and in the inline and harness connectors at the sensor and ECM.