FI SYSTEM AND INTAKE AIR SYSTEM 4-21
Secondary throttle valve
Secondary throttle
valve actuator
OPERATION
The secondary throttle control system (STC system) operates on the signal supplied from the ECM. The
open/close operation of the secondary throttle valve (ST valve) is performed by the secondary throttle valve
actuator (STV actuator) which is controlled by the ECM to change the current direction into the motor of the
STV actuator.
The motor and the position sensor are located inside the STV actuator.
The position sensor detects the STV actuator movement by measuring voltage and the ECM determines
the ST valve angle based on the operation map.
When turning the ignition switch ON, every time the STV actuator automatically drives the valve and checks
fully the close and open position voltage and return to fully close position to confirm each position at the
STV actuator side. Valve angle is controlled by the ECM.