Electronic throttle control is intentionally redundant because a false throttle command can be dangerous. The accelerator pedal may have two tracks, the throttle body may have two position tracks, and the ECU monitors motor current and movement. The system checks whether all of these pieces agree.
If APP track 1 moves smoothly but APP track 2 drops out at mid travel, the pedal assembly or wiring is suspect. If both APP tracks are correct but throttle position does not follow command, the issue may be in the throttle motor, power supply, mechanical plate or throttle-body electronics. If the plate reaches the requested angle but airflow remains wrong, look beyond the position sensor.
Graph related PIDs together. The visual relationship is often more informative than individual numbers. Do not manually force the throttle plate unless service information allows it, and perform relearn procedures when required after replacement or cleaning.
Reduced-power mode is a safety response. Treat it as a clue to correlation failure rather than as the fault itself.