DTC P0121-P0123: Throttle Position (TP) Sensor Circuit: Description

TP sensor signal informs ECM of actual throttle position and rate of change in throttle position. ECM cross checks TP sensor output with Mass Airflow (MAF) sensor output. If values from these two sensors do not agree and fuel injection feedback indicates correct air/fuel mixture, ECM assumes MAF sensor is correct and TP sensor has failed. A TP sensor failure may result in no idle speed control, poor engine idle and/or poor throttle response.