A diagnostic system for an electric power steering system, comprising: a first microprocessor configured to receive first and second signals (MPS_Sin, MPS_Cos) from first and second position sensors , respectively, disposed in a motor of the electric power steering system, the first and second signals (MPS_Sin, MPS_Cos) being indicative of a relative rotational position of a magnet disposed on a rotatable shaft of the motor , the first microprocessor further configured to determine a first relative position value indicating the relative rotational position of the rotatable shaft at a first time based on the first and second signals (MPS_Sin, MPS_Cos); third and fourth position sensors disposed proximate to the rotatable shaft and outside of the motor , the third and fourth position sensors configured to generate third and fourth signals (TC_Sin, TC_Cos), respectively, indicative of the relative rotational position of the magnet on the rotatable shaft ; a second microprocessor configured to receive the third and fourth signals (TC Sin, TC Cos) and to determine a second relative position value indicating the relative rotational position of the rotatable shaft at the first time based on the third and fourth signals (TC_Sin. TC_Cos); the second microprocessor further configured to send the second relative position value to the first microprocessor ; and the first microprocessor further configured to determine a difference between the first relative position value and the second relative position value; and the first microprocessor further configured to store a diagnostic value in a memory device indicative of whether the second relative position value is acceptable based on the difference between the first relative position value and the second relative position value. a first microprocessor configured to receive first and second signals (MPS_Sin, MPS_Cos) from first and second position sensors , respectively, disposed in a motor of the electric power steering system, the first and second signals (MPS_Sin, MPS_Cos) being indicative of a relative rotational position of a magnet disposed on a rotatable shaft of the motor , the first microprocessor further configured to determine a first relative position value indicating the relative rotational position of the rotatable shaft at a first time based on the first and second signals (MPS_Sin, MPS_Cos); third and fourth position sensors disposed proximate to the rotatable shaft and outside of the motor , the third and fourth position sensors configured to generate third and fourth signals (TC_Sin, TC_Cos), respectively, indicative of the relative rotational position of the magnet on the rotatable shaft ; a second microprocessor configured to receive the third and fourth signals (TC Sin, TC Cos) and to determine a second relative position value indicating the relative rotational position of the rotatable shaft at the first time based on the third and fourth signals (TC_Sin. TC_Cos); the second microprocessor further configured to send the second relative position value to the first microprocessor ; and the first microprocessor further configured to determine a difference between the first relative position value and the second relative position value; and the first microprocessor further configured to store a diagnostic value in a memory device indicative of whether the second relative position value is acceptable based on the difference between the first relative position value and the second relative position value. <EOS>