Honda developed a technology to quantify automotive steel corrosion from the rust reduction current detected by a proprietary developed sensor. The values calculated based on Faraday's law did not match the actual measured values for the mass loss of iron due to the added resistance of rust formed between electrodes on the sensor. It was determined that the resistance of rust depends on the environment, and this issue was resolved by setting the correction values for that influence. As a result of this research it was found that the values calculated from the sensor measurements matched those from the mass loss of test specimen on a vehicle. Honda is utilizing this newly developed technology for corrosion research and field data collection.