1. A method for determining the state of health of a starter motor in a vehicle, said method comprising: using a current sensor to determine a starter motor current of the starter motor; using a voltage sensor to determine a starter motor voltage of the starter motor; providing an engine speed of an engine of the vehicle; identifying starter motor values that will be used to determine the state of health of the starter motor, wherein the starter motor values are a starter motor resistance that is the combination of a starter motor armature resistance and a starter motor brush resistance, a starter motor armature inductance and a back EMF motor constant; identifying a time model of the starter motor using the starter motor voltage, the starter motor current, the engine speed and the starter motor values; defining model parameters from the time model; providing a regression model based on the time model; using a controller to determine motor parameters based on the regression model; using the controller to determine an error using the motor parameters; and using the controller to compare the error to an error threshold to determine the state of health of the starter motor.