: If the line is not shorted but the voltage is missing, the issue may lie within the USB controller IC (U6300 Hydra or Kraken) or the Charging IC (Yangtze/Tigris). Repair Wiki capacitor reference designators for a different iPhone model or how to perform a diode mode test on this specific rail? IPhone Charging Circuit Diagnostics Guide - Repair Wiki
Here is the breakdown of the component parts: pp-var-usb-rvp
So one plausible guess:
A -.-> K[Detection Signal<br>HYDRA_CON_DETECT_L] K -.-> H : If the line is not shorted but
: Stable power on this line ensures that the USB data pins (D+ and D-) can transmit information without interference from electrical noise. 💡 Future of Power Connectivity HYDRA_CON_DETECT_L] K -.->