Abstract :
Based on the results of interviews and observations made at the Nissan Probolinggo dealership, 6 parameters were obtained to be used as variables in the study. The methodologies used in the research include requirements analysis, system design, implementation, and testing. The algorithm used is K-Nearest Neighbor and Certainty Factor. In the K-Nearest Neighbor method, it runs based on the training data tested and the number of data from the nearest neighbors or the number of K. While Certainty factor is a method that runs based on the assessment of experts in their fields, in this case, is a car expert. This system generates a classification for the new data and the confidence value of the inputted data. The accuracy of the KNN method used for classification is 80%.