The DOT code is the serial code located in the lower sidewall after the word 'DOT'. The complete DOT code typically contains a group of up to 13 characters (letters and numbers). In the photo below, the DOT code is 1YJ FYNTLY 1117 – Important: The last four digits indicate the week and year of manufacture. For example, week 11, year 2017. The complete DOT code, including date, can only be found on one side of the tire. Depending on how your tires were mounted, it could be on the inside.