The corrosion behavior of X33CrNiMn23-8, X50CrMnNiNbN21-9 and X53CrMnNiN20-8 steels utilized in automobile industry has been studied in oxidizing atmosphere, containing water vapor and acetic acid, usually present in combustion gases of biofuels in car engines. It has been found that the mechanism of corrosion under these conditions is rather complex. After early stages of the reaction, not exceeding 40 hours, the process follows approximately parabolic kinetics, being thus diffusion controlled. It has been shown that the presence of acetic acid highly increases corrosion rate of X33CrNiMn23-8 steel, containing highest chromium content, but has virtually no influence on the corrosion rate of X50CrMnNiNbN21-9 steel with lowest chromium concentration. These differences have been explained in terms of phase and chemical composition of corrosion products.