DTC P1512: Command Vs. Actual Throttle Position Correlation Error: Description
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The commanded throttle position is compared to the actual throttle position based on accelerator pedal position and possibly other limiting factors. Both values should be within a calibrated range of each other. The Powertrain Control Module (PCM) continuously monitors the commanded and actual throttle positions. This Diagnostic Trouble Code (DTC) sets if the values are greater than the calibrated range.