Comments: Customers replacing this DEF sensor must order the kit corresponding to their model and serial number as follows: For models 642, 742, 943 & 1043 order kit 1001238953 for all serial numbers. For models 1055 and 1255 serial numbers 0160069775 thru 0160075365 including 0160066472, 0160067787 and 0160067789, order kit 1001238953. For models 1055 and 1255 serial number 0160075366 to present, order kit 1001239095.