DTC P2121: Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance [08/2013 - ]: Fail-Safe
The accelerator pedal sensor assembly has 2 (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM limits the engine output. If both circuits malfunction, the ECM regards of the accelerator pedal angle as being fully closed. In this case, the throttle valve remains closed as if the engine is idling.