VC Output Circuit [08/2020 - ]: Description
WARNING: This page is about a different car, the 2021 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B, +B2 (BATT) terminals to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.
When the VC circuit has a short circuit, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are deactivated because power is not supplied from the VC circuit. When the system is in this condition, it will not start.