Circuit Description

Throttle Position (TP) sensor is mounted on throttle body and detects throttle opening angle. When throttle valve is fully closed, at engine idle, about .3-.8 volt is applied to TP sensor input circuit. Voltage will increase in proportion to amount of throttle valve opening angle. At Wide Open Throttle (WOT), TP sensor input circuit voltage is about 3.2-4.9 volts. PCM determines vehicle driving condition from TP sensor input and calculate air-fuel ratio correction, power increase correction and fuel-cut control. DTC P0120 will set when:

• TP sensor input to PCM is greater than one volt and throttle valve is in closed position.
• TP sensor input to PCM is less than 4.9 volts and throttle valve is at WOT position.

When DTC sets, MIL will illuminate. PCM will record operating conditions at time of failure and store information in freeze frame buffer. TP sensor angle will default to zero percent.