DTC P0121: General Description
The electronic throttle control system controls the throttle valve opening. The system includes the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the PGM-FI subrelay circuit, the accelerator pedal position (APP) sensor, and the powertrain control module (PCM). TP sensor A is a semiconductor type, and it is attached to the throttle body and shaft to determine throttle valve position. The throttle valve position signal from TP sensor A is transmitted to the PCM for target position feedback control. If the signal from TP sensor A is a fixed value for a set time, the PCM detects a TP sensor A malfunction and stores a DTC.