DTC P0123: Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

This diagnostic monitors the throttle position (TP) sensor 1 signal. There are two TP sensors located on the throttle body inside of the throttle actuator control (TAC) module. All throttle control is performed by the TAC system. The TP sensors, along with the accelerator pedal position (APP) sensors and the TAC module are mandatory components of the TAC system. The TP sensors are used to determine the throttle plate angle. The TP sensor is a potentiometer whose resistance value changes along with the throttle valve position. The sensor uses a 5-volt reference supply, a low reference and a signal circuit. The TAC module the signal circuit voltage to calculate the actual throttle valve opening. The TP sensor is an integral part of the TAC module is not serviced separately. Installing a new TP sensor requires the replacement of the throttle body assembly. For additional information on the operation of the TP sensor and the TAC system refer to Throttle Actuator Control (TAC) System Description . If the TAC module detects that the TP sensor 1 signal voltage is too high it reports the malfunction to the powertrain control module (PCM) and the PCM sets this DTC.