DTC P1221: Excessive Difference Between Throttle Position Sensors: Description

The throttle actuator control assembly has two Throttle Position (TP) sensors mounted within the assembly. The Powertrain Control Module (PCM) provides individual signal, ground, and 5-volt reference circuits to each sensor. Both sensors operate within a voltage range between 0.35-4.65 volts. When the throttle is opened from 0 to 100 percent, one sensor signal voltage increases while the other decreases. The signal circuit for TP sensor 1 is referenced to ground, and the signal circuit for TP sensor 2 is pulled up to 5 volts within the PCM.