Fuel Rail Pressure Sensor signal. This is a 0.5V to 4.5V signal that tells the ECU how much pressure is in the rail.
There are "Normally Open" and "Normally Closed" SCVs depending on the year. Ensure your ECU part number matches the pump type. toyota 2kdftv ecu pinout diagram best
Immobilizer Input/Output. If you are doing an engine swap, the ECU will look for a "handshake" here. If it doesn't receive it, the injectors will remain locked. Wiring for Swaps: The "Standalone" Essentials Fuel Rail Pressure Sensor signal