2003 Toyota Hilux 3.0 l 1KZ_TE engine control Manual
S409 is a first gear selection indication, When the switch is on all the time, the ECU will cut the fuel supply to the injectors and limit the power and torque to the wheels, as it means the first gear is selected. Hence we feel lack of power. In this senior there is no MIL light on or any DTC lodged.