(Torque Based) Electronic Throttle Control (ETC): Overview

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

The Generation II (Gen II) torque based electronic throttle control (ETC) is a hardware and software strategy that delivers an engine output torque (via throttle angle) based on driver demand (pedal position). It uses an electronic throttle body, the PCM, and an accelerator pedal assembly to control the throttle opening and engine torque. The ETC system replaces the standard cable operated accelerator pedal, idle air control (IAC) valve, 3-wire throttle position sensor (TPS), and mechanical throttle body.

Torque based ETC enables aggressive automatic transmission shift schedules (earlier upshifts and later downshifts). This is possible by adjusting the throttle angle to achieve the same wheel torque during shifts, and by calculating this desired torque, the system prevents engine lugging (low RPM and low manifold vacuum) while still delivering the performance and torque requested by the driver. It also enables many fuel economy/emission improvement technologies such as variable cam timing (VCT) (deliver same torque during transitions).

Torque based ETC also results in less intrusive vehicle and engine speed limiting, along with smoother traction control.

Other benefits of ETC are:

Eliminate cruise control actuators.
Eliminate idle air control (IAC) valve.
Better airflow range.
Packaging (no cable).
More responsive powertrain at altitude and improved shift quality.

It should be noted that the ETC system includes a warning indicator (wrench light) on the instrument cluster that illuminates when a fault is detected. Faults are accompanied by DTCs and may also illuminate the malfunction indicator lamp (MIL).