Circuit Description

The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually two individual TP sensors within one housing. Two separate signal, low reference and 5-volt reference circuits are used to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to reference voltage as the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and accelerator pedal position (APP) sensor 1 share a 5-volt reference circuit that are connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that are connected within the TAC module. If an out of range condition is detected with the TP sensors, this diagnostic trouble code (DTC) will set and the Reduced Engine Power message will be displayed.