Diagnostic system for a vehicle electrical system

A diagnostic system for a vehicle electrical system, wherein the vehicle electrical system has a battery module, a contactor, a high side driver circuit, a low side driver circuit, and a voltage regulator outputting a first voltage, the diagnostic system comprising:

• a first voltage divider circuit receiving the first voltage and outputting a second voltage in response to the first voltage,
• a second voltage divider circuit receiving the first voltage and outputting a third voltage in response to the first voltage;
• a first analog multiplexer having an input port that receives the second voltage from the first voltage divider circuit;
• a second analog multiplexer having an input port that receives the third voltage from the second voltage divider circuit;
• an analog-to-digital converter being electrically coupled to an output port of the first analog multiplexer and an output port of the second analog multiplexer, the analog-to-digital converter receiving the second and third voltages at first and second times, respectively, and outputting first and second voltage values respectively, based on the second and third voltages, respectively, that are received by a microcontroller;
• the microcontroller determining a first compensated voltage value utilizing the first voltage value and a compensation value;
• the microcontroller determining a difference value based on the first compensated voltage value and the second voltage value;
• and
• the microcontroller commanding the high side driver circuit and the low side driver circuit to transition a contact of the contactor to an open operational position when the difference value is greater than a threshold difference value indicating that the analog-to-digital converter is malfunctioning.