What is the high‑voltage interlock loop (HVIL), and why is it important during service?

• A. HVIL is the safety interlock circuit that ensures the HV system is automatically de‑energized if a cover or connector is opened or mismatched; it prevents energizing hazards.
• B. HVIL is a fuse.
• C. HVIL is a type of battery.
• D. HVIL is a software feature.

Answer: (A)

HVIL is a safety interlock circuit that ensures the high-voltage system is automatically de-energized if a cover or connector is opened or mismatched, preventing energizing hazards. This matters during service because technicians may need to access HV components, and opening protective panels or disconnecting parts should immediately isolate the high-voltage system to prevent shock, burns, or arc flash. The interlock loop is monitored by the vehicle’s HV control system, and if the loop is broken or a mismatch is detected, the high-voltage supply is shut off. It’s not a fuse, not a battery, and not a software feature—it's a hardware safety mechanism that protects you while you service the vehicle.