DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage Circuit Description The PCM supplies a 5V reference signal and a ground to the sensor. The TP sensor sends a voltage signal back to the PCM relative to the throttle plate opening. The voltage will vary from approximately 0.45Vat closed throttle, to over 4.5V at wide open throttle. Conditions for Setting the DTC • Engine is running. • TP sensor is less than 0.19 V for 5 seconds.