In SAE J1939, the acronym PDU2 stands for Protocol Data Unit 2 and represents a message that is not destination specific, which is also referred to as a global destination message. If a message is a PDU1 or PDU2 format is specified by the protocol format (PF) field contained in the PGN.

A PF field greater than or equal to 240 indicates a PDU2 format message. The PDU format entity was created to allow for the maximum number of PGNs but still allowing for destination specific messages.