How can you prevent vehicle movement while working on the HV system?

• A. Engage the parking brake, use wheel chocks, and remove the ignition key; ensure the vehicle is in a safe gear state as per OEM.
• B. Disconnect the battery cables only.
• C. Just place the vehicle in park and walk away.
• D. Use a flagging tape around the vehicle.

Answer: (D)

To prevent movement while you work on the HV system, you must physically immobilize the vehicle with multiple safeguards. Engage the parking brake, place wheel chocks against the appropriate wheels, and remove the ignition key to prevent anyone from starting the vehicle. Set the transmission to the safe gear state specified by the OEM (often Park for automatics, or the recommended neutral/parking protocol for manuals). These measures create real barriers to any unintended roll or startup, which is essential when working around high-voltage systems. Disconnecting battery cables alone does not reliably stop movement, and simply putting the vehicle in park and walking away leaves you exposed to a potential roll if the brakes fail or if someone inadvertently moves the vehicle. Flagging tape is about marking the area, not securing the vehicle, so it doesn’t prevent movement.