Throttle Control
Some models use a Throttle Actuator Control (TAC) system to calculate and control the position of throttle plate electronically. This eliminates the need for a mechanical cable attachment from accelerator pedal to throttle body. The TAC system consists of an Accelerator Pedal Position (APP) sensor, throttle body/actuator assembly, Throttle Actuator Control (TAC) module and Powertrain Control Module (PCM). Cruise control functions are also performed by the TAC system.
The throttle actuator is an electric motor attached to throttle body and responds to command signals received from the TAC module. As vehicle operator moves accelerator pedal, a signal is sent to TAC module. A command is then sent to throttle actuator to adjust throttle plate accordingly. The PCM communicates with TAC module to compare values of Throttle Position (TP) sensor, APP sensor and other various engine sensors. A diagnostic trouble code will set if actual throttle angle measured by TP sensor does not match sensor values sent by the APP sensor.