Circuit Description

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The Throttle Position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-volt reference circuit and a common low reference circuit. The 5-volt reference circuit is also shared with Accelerator Pedal Position (APP) sensor 2. The 5-volt reference voltage is supplied on 2 separate Engine Control Module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to throttle the plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. The TP sensor 2 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. The ECM compares the signal of the throttle position sensors to the predicted TP sensor signal, based on calculations from the Mass Airflow (MAF) sensor. The control module also compares the signal of the TP sensor 1 and TP sensor 2 through the entire range. If ECM detects a difference from the predicted range of more than 6 percent between sensor 1 and sensor 2, DTC P2135 sets.