ECT or Electronically Coontrolled Transmission is Toyotas version of an electronic slushbox. The transmission itself is very similar to an hydraulic controlled transmission save for the additiomn of valve body and speed and other sensors. Cars that come factory equipped with ECT/TEMS (Toyota Electronic Modulated Suspension) Have an ECT/TEMS ECU besides the Engine ECU.
The ECT allows for two different shit and lockup maps as designated on the Switch. Normal and Power (PWR). In power mode, upshift would occur later corresponding to throttle opening (Throttle position sensor) and Vehicle speed sensor)