Most folks don't realize the car has an interlock jumper built into the service plug to notify the HV ECU that it's all the way seated. The idea being that if someone starts to remove the plug when the car is ready on, the ECU can open the main relays ahead of time, avoiding a possible spark.

In any case, without the plug all the way snapped down towards the floor of the car, the jumper will not seat, the circuit will be open, the car will not start and code P0A0D info code 350 will be stored.