AbstractChina's automotive industry has entered a stage of great growth. Owing to the widespread and rapid information dissemination of online automotive forums, they have become an important source for manufacturers to collect product defect information and understand consumer preferences. The purpose of this study is to investigate car defect information and consumer preferences from online automotive forums and segment consumers based on consumer preferences, which holds great promise as a means for companies to improve product design and consumer relationship management. Based on text data of China's top‐ranked Pacific Auto Network, we applied the LDA model, sentiment analysis, text classification, and cluster analysis methods to determine the influencing factors of automobile consumers’ purchasing behavior, identified automobile product defects, and subdivided consumer groups. The results show that the factors affecting consumers’ car buying behavior are low fuel consumption, affordable price, superior performance, fashionable appearance, and comfortable use. Car product defects are mainly reflected in the three aspects of the car's performance, comfort, and configuration; there are six kinds of consumer groups: price seekers, fuel consumption seekers, performance seekers, comfort seekers, cost performance seekers, and appearance seekers. Of these, cost performance seekers make up the largest proportion, and they constitute the largest group of intention purchasers. These findings can help enterprises develop targeted product improvement programs, but also provide a decision‐making basis for enterprises to achieve precision marketing.