Electronic Throttle Control
Overview
The electronic throttle control system (ETCS) opens and closes the throttle valve by electronic control. This system consists of a throttle actuator built into the throttle body, throttle valve, and throttle position (TP) sensor A/B, accelerator pedal position (APP) sensor A/B, the ETCS driver built into the powertrain control module (PCM), and the ETCS control relay (in the under-hood fuse/relay box) that supplies power to the ETCS driver.
ETCS is a system that opens and closes the throttle valve electronically, it has various functions such as:
- Idle Control Function
Where the throttle position is controlled to optimize idle speed depending on the engine loads when idling.
- Accelerator Control Function
Where the target throttle position is calculated by the throttle position sensor signals to control the throttle valve when the accelerator pedal is pressed.
- Transmission Control Function
Where the throttle valve is controlled in coordination with the transmission to reduce shift time.
- VSA Control Function
Where the throttle position is controlled based on a signal from the VSA modulator-control unit.
- Fail-Safe Function
Where the throttle valve is controlled to avoid danger even in the event of a malfunction.
Control
When the accelerator pedal is operated, APP sensors are driven and the accelerator pedal position is detected. The accelerator pedal position is delivered to the PCM, and the PCM drives the throttle actuator in the throttle body based on the delivered throttle pedal position to open or close the throttle valve.
Throttle position is detected by the TP sensors in the throttle body and delivered to the PCM.
The PCM drives the throttle actuator to control the throttle position during idling, when the VTEC system switches, when shifting, during VSA control, and when necessary, as well as based on the signals from the APP sensors.