Almost finished my harness for retrofitting a LSA 2013, 6L90E combo.
I got the engine and trans running on a pallet so its just a couple of things left.

I got an error code because I have no brake bedal sensor.
DTC is P057C Brake pedal position sensor circuit low voltage

The sensor that I dont have seems to have two circuits, one to the BCM and one to the ECU -> CAN -> TCM.
I do believe I only need the circuit to the ECM. Looking in the diagram its a 0-5V signal with 3 wires.

X3, pin 27, WH, Brake Apply Sensor Low Reference
X3, pin 43, TN, Brake Apply Sensor Voltage Reference
X3, pin 63, YE, Brake Position Sensor Signal

Do I really need position sensor that tracks the pedal movement?
Can I wire in a relay on the 5v and a resistor controlled by the cars brake switch?
Do I need to calibrate the brake pedal sensor to (not available in EFI live I guess)?