FMC640 J1708

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SAE J1708 is a standard used for serial communications between ECUs on heavy-duty. The hardware utilized is RS-485 transceivers wired for open collector operation through the use of a pullup and pulldown of the separate data lines.

With FMC640, J1708 functionality is used to read vehicle's Fuel Level and Fuel consumption.

Because J1708 is not a CAN-BUS protocol, FMC640 CAN1 and CAN2 lines cannot be used to read J1708 information. FMC640 has a special J1708 Port, which utilizes an RJ9 4P4C connector.

FMX640 and J1708 illustration v1.2.png

Software Configuration of FMC640 with J1708

J1708 configuration is done in the FMS IO Tab.

J1708 config.gif

When J1708 is enabled as a Fuel Level source, Fuel-related data will be taken from the J1708 line, FMS Fuel data will be ignored.

Connection with Vehicle port

J1708 connector is not supported by all vehicles. Only VOLVO, RENAULT, and American truck manufacturers implement the J1708 connector.

Trucks utilize Deutsch 6-PIN or Deutsch 9-PIN connector, which are used to connect FMC640 to J1708.

FMX640 and 6PIN J1708 connection scheme v1.2.png FMX640 and 9PIN J1939 connection scheme v1.1.png

NOTE: Most of the Volvo trucks need an J1708 connection to be able to receive fuel level data