DTC P2100-18: Throttle Actuator "A" Control Motor Circuit Current Below Threshold; DTC P2100-19: Throttle Actuator "A" Control Motor Circuit Current Above Threshold [08/2020 - ]: Fail-Safe
WARNING: This page is about a different car, the 2021 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
When these DTCs are stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator, and the throttle valve is returned to a 7.5° throttle valve opening angle by the return spring. The ECM then adjusts the engine output by controlling the fuel injection (intermittent fuel-cut) and ignition timing, in accordance with the accelerator pedal opening angle, to allow the vehicle to continue running at a minimal speed. If the accelerator pedal is depressed firmly and gently, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the engine switch is turned off.