DTC P1516: Predicted Vs Actual Throttle Position Correlation Error: Description
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The predicted Throttle Position (TP), based on Accelerator Pedal Position (APP) and other limiting factors, is compared to the Actual throttle position. The two values should be within a calibrated range of each other. Both the Powertrain Control Module (PCM) and the Throttle Actuator Control (TAC) module redundantly monitor the predicted and actual throttle position. This DTC sets if the PCM detects an out of range condition between the predicted and actual throttle position.