How do you clear codes in a 2009 peterbilt?

To clear codes in a 2009 Peterbilt, you typically need to use a diagnostic scanner or code reader compatible with the vehicle's engine control module (ECM). Connect the scanner to the diagnostic port, turn on the ignition without starting the engine, and follow the scanner's prompts to clear the codes. Alternatively, you can disconnect the battery for a few minutes, but this method may also reset other systems. Always ensure to address the underlying issue before clearing the codes to avoid potential problems.