The shear-stress-transport (SST) turbulence model is one of the best comprehensive two-equation turbulence models available and is widely used in the research of automotive aerodynamics. The existing studies have shown that the closure coefficients in the turbulence model significantly affect the accuracy of aerodynamic simulation for vehicles. However, most researches are limited to simplified models. Therefore, in this paper, the impact of the typical turbulence model coefficients on the accuracy of aerodynamic simulations of a sedan is studied under stationary wheel conditions. It is found that the turbulence model coefficients and are linearly related to aerodynamic drag and lift, while approximately quadratic for . Furthermore, this paper uncovers the influence mechanism of turbulence model coefficients on the flow field around the vehicle, and the recommended values for turbulence model coefficients to improve the accuracy of aerodynamic simulation are provided: , , , and .This paper provides theoretical and engineering guidance for more accurate and reliable aerodynamic simulation of vehicles.