Diagnostic system for a hybrid electric vehicle

A diagnostic system for a hybrid electric vehicle, comprising:

• a vehicle controller being operably coupled to a battery management controller;
• the battery management controller being operably coupled to a monitoring circuit;
• the vehicle controller sending a first message to the battery management controller indicating an engine crank occurred;
• the battery management controller sending a second message to the monitoring circuit in response to the first message, the second message indicating that a diagnostic test is to be initiated;
• the monitoring circuit outputting a first signal which induces a transistor to turn off which de-energizes a voltage coil of an electrical relay in response to the second message to initiate the diagnostic test;
• a voltage sensor outputting a voltage signal indicative of a voltage being output by the transistor to the voltage coil;
• the analog-to-digital converter receiving the voltage signal and outputting a voltage value based on the voltage signal;
• and
• the battery management controller receiving the voltage value and setting a diagnostic flag to a first value if the voltage value is less than a threshold voltage value, the first value indicating that the diagnostic system is operating as desired to detect a fault condition.