DTC P1220: Throttle Position Sensor 2 Circuit: Description

WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. 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. Each sensor has the following components:

A 5-volt reference circuit.
A low reference circuit.
A signal circuit.

This provides the Powertrain Control Module (PCM) with a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage at closed throttle is about the 5-volt reference and decreases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is about the low reference and increases as the throttle plate is opened. When TP sensor 2 signal voltage is not within the predicted range, this DTC sets.