The document provides clarity related to multiple temperature coolant circuits used with on-highway and off-highway, gasoline, and light-duty to heavy-duty diesel engine cooling systems, or hybrid vehicle systems. These multiple temperature systems include engine jacket coolant plus at least one lower temperature system.
Out of scope are the low temperature systems used in electric vehicles. This subject is covered in SAE J3073. Note that some content in SAE J3073 is likely to be of interest for hybrid vehicles.
Out of scope are the terms and definitions of thermal flow control valves used in either low-temperature or high-temperature coolant circuits. This subject is covered in SAE J3142.