J1939 Installation Overview

Certain engine and generator manufacturers do not support NMEA 2000 but do support J1939. When an engine or generator doesn’t support NMEA 2000, a J1939 to NMEA 2000 converter box can be used to send engine data to a supported Garmin chartplotter. 

However, Garmin has started producing chartplotters that have a dedicated J1939 port. With the addition of the J1939 port, these chartplotters are enabled to directly interface to a J1939 engine or generator. Note there can only be one J1939 connection per Garmin chartplotter with a J1939 port. If multiple J1939 devices exist on a vessel, multiple Garmin chartplotters with a J1939 port will be required to interface to each J1939 device. If a J1939 enabled chartplotter is not available for each J1939 enabled device a J1939 to NMEA 2000 converter will need to be installed for each J1939 enabled engine or generator to transfer data to the chartplotter so the additional device data can appear on the network. See examples below. 

PGN's that are supported:

• Engine RPM - 61444

• Exhaust Temp - 65031

• Engine Hours - 65253

• Coolant Temp / Pressure - 65262

• Oil Temp / Pressure - 65263

• Transmission Fluid Temp / Pressure - 65272

• Fuel Rate - 65266

• Diagnostic Trouble Codes - 65226

• Generator Frequency / Current / Voltage - 65030

• Battery Voltage / Current - 127508

Examples of Common Installations:

                       Single Engine with Multiple Chartplotters

                            Two Engines with Two Chartplotters                                                            Two Engines with a Single Chartplotter Requires a Gateway                                   

                                     Three Engines with Two Chartplotters Requires a Gateway

Additional considerations to be aware of:

• J1939 installation should be reserved more for the installer/OEM

• Installation consists of a single J1939 cable from a J1939 bus, routed to either an MFD or a gateway

• There is a limit of one J1939 cable per bus

  • This cable is bare wire and the installer will need to get the appropriate connector from the bus manufacturer

• Some engine manufactures can have multiple engines on a single J1939 bus (I.E Volvo and Cummins)

• For engine manufacturers that don’t support multiple engines on a single J1939 bus:

  • A gateway will be necessary if there are multiple engines but just a single display

  • If there are two displays and two engines then a gateway is not needed because each engine will have its own bus, which will connect to its own MFD

• Not all information that is received via J1939 can be transmitted via NMEA 2000 (this information will only be seen by chartplotters receiving data being bridged from Garmin Marine Network to NMEA 2000)

• When a J1939 Yamaha engine is connected to the port on the chartplotter the Yamaha gauge page will display