Check engine light came on Saturday morning after about a 10 mile drive. Scan tool tells me the code is P057B. The book that came with the tool did not have that exact code, and searching on the internet has been less than successful. Oil was changed 11/24, DEF filled 10/25, Fuel filter at 85% per DIC, all gauges and fluid levels check out. I fueled up the day before and only had about 35 miles on that tank of fuel, but filled up at large chain fuel station that sees many trucks daily. The light has since gone off, but if someone has experience with the code so I can have a little more information before I take to the dealer. Thanks in advance.