Patent attributes
A diagnostic system for a hybrid electric vehicle is provided. The system includes a vehicle controller, a battery management controller, a monitoring circuit, a transistor, a voltage sensor, and an analog-to-digital converter. The vehicle controller sends a first message to the battery management controller indicating an engine crank occurred. The battery management controller sends a second message to the monitoring circuit, and the monitoring circuit induces a transistor to de-energize an electrical relay. The voltage sensor outputs a voltage signal indicative of a voltage being output by the transistor. The analog-to-digital converter outputs a voltage value indicative of the voltage. The battery management controller sets a diagnostic flag to a first non-fault value if the voltage value is less than a threshold voltage value.
