Parameter 2: Diagnostic Trouble Code (DTC) with three byte length 2) Sub-Functions for Service $19 Read DTC Information Hex Description 01 Report number of DTC by Status Mask ... 15 Report DTC with Permanent Status UDS and OBD Positioning in the ISO/OSI Layer Model
Numerical data that is larger than a single byte is sent with least significant byte (LSB) first. J1939 uses CAN 2.0B with the extended (29 bit) identifier. The CAN identifier consists of a priority(3 bits), a reserved (1 bit), a data page (1 bit), PDU format (one byte), PDU specific (one byte) and source address (one byte).