Apparatus and method for detecting failure of torque sensor for motor-driven power steering system

A processor-implemented method of detecting a failure of a torque sensor for a motor-driven power steering system of a vehicle, the method comprising:

• storing torque sensor failure information in a memory;
• in response to a detection result indicating that a first torque sensor and a second torque sensor are normal, comparing a first torque value of the first torque sensor with a second torque value of the second torque sensor, and determining whether a result of the comparison is abnormal;
• in response to the comparison result being abnormal, applying an electric current to a motor of the motor-driven power steering system, the electric current having a predetermined magnitude and being applied for a predetermined time to provide a small amount of vibration in the steering system, to measure an amount of change in the first torque of the first torque sensor and an amount of change in the second torque of the second torque sensor;
• selecting, by a processor, a normal torque sensor from among the first torque sensor and the second torque sensor, in response to the vehicle being turned on;
• detecting, by the processor, a failure of at least one of the normal torque sensor or the other torque sensor while controlling the motor using a torque signal from the normal torque sensor;
• and
• updating, by the processor, the torque sensor failure information based on a failure detection result, in response to the vehicle being turned off,
• wherein applying the electric current to the motor to determine the failure is performed only when a difference between the first torque value and the second torque value exceeds a third reference torque value and is less than or equal to a fourth reference torque value for at least a third reference time, or when the difference exceeds the fourth reference torque value for at least a fourth reference time.