Which application standard allows the DCS and the ECMs on the BPU to control all engine functions?

The correct choice is based on the role of the SAE J1939 standard in providing a set of communication protocols for vehicles, particularly regarding heavy-duty truck and off-highway equipment networks. This standard enables interoperability between various electronic control modules (ECMs), including those found in distributed control systems (DCS) like the BPU (Basic Power Unit).

SAE J1939 outlines the message formats and communication requirements essential for engine control, allowing different components of an engine system to interact and manage functions such as speed, temperature, and fuel flow. This capability is crucial for system integration, ensuring that all engine functions can be accurately and efficiently controlled by the DCS and ECMs.

The presence of other options, like ISO J1939, can cause some confusion; however, the correct designation is indeed SAE J1939, which reflects its origin from the Society of Automotive Engineers and its primary application in vehicle communication networks. This distinction is important because it ensures adherence to industry standards that enhance compatibility and functionality across different manufacturers and systems.