Emissions-related data is critical for fleets to measure and manage.

Electronic control modules (ECMs) broadcast a steady stream of files and information through a vehicle’s controlled area network (CAN). Thousands of fleets are using their onboard computing and mobile communications platforms to manage some of this information — idle time, speed, mpg and engine fault codes, etc. — remotely.

The information comes in a standard format or protocol called J1708 and J1939 for heavy-duty trucks and OBD-II for light-duty vehicles. Since 1996, heavy-duty vehicle manufacturers have used the J1708 protocol. Since 2003, they have been migrating toward J1939. Several vehicle manufacturers now are using only J1939 for their 2010 model trucks.

Companies that own equipment before and after 2003, therefore, operate a “mixed” fleet in term of information capabilities. The J1939 is a newer system with a different interface structure, and it manages more data communication than J1708.

“If J1939 is present, we use this data,” says Norman Thomas, vice president of information consulting for CarrierWeb, which offers the CarrierMate onboard computing and communications platform. “If not, then we use J1708 as all larger trucks still have J1708.”

A few examples of the new data offered on J1939 include fuel level, seat belt use and new diagnostics trouble codes. “J1708 offers fuel burn and mpg, but generally not fuel level, which is desired to monitor that fuel purchases are completely inserted into the vehicle tank and to be sure none is siphoned out,” Thomas says.

Another advantage of J1939 is that it allows third-party applications in a vehicle — such as stability control and lane departure warning systems — to broadcast critical event data. This data can be picked up from the J1939 by an onboard computer.

PeopleNet, an onboard computing and mobile communications provider, captures data from a vehicle through its PerformX vehicle performance monitoring and reporting tool. The company recently enhanced PerformX with a “multibus” adapter to capture both J1708 and J1939 data.

“Having the ability to integrate to J1939 allows us to collect vehicle and third-party application data that reside on a vehicle,” says Tom Dorazio, product manager for PeopleNet’s vehicle integration products.