Current sensor fault diagnostics

A battery electric system includes a battery, sensor suite, and controller. The sensor suite includes a current sensor, voltage sensor, and temperature sensor. The controller is operable for determining an estimated open circuit voltage of the battery at different time points using a current signal and a voltage signal from the current and voltage sensors, and an equivalent circuit model (ECM). The controller determines an ECM-based state of charge (SOC) of the battery at the different time points, via a calibrated SOC map, using the open circuit voltage and temperature, and calculates a sensor gain value using the ECM-based SOC and a coulomb counting-based SOC, both at the different time points. A control action is executed with respect to the battery when the sensor gain value exceeds a predetermined gain fault threshold, including generating a fault notification signal indicative of a fault of the current sensor.