OBDII & J1939 Diagnostic Interfaces

Question

My rig has both diagnostic interfaces and I assume many others do as well.

The standard 16 pin OBDII connector on my Workhorse Chassis supports J1850 VPM protocol. Anyone know if the J1939 9-pin round connector offers a different or a super set of the ECM data as compared to the 16-pin OBDII interface?

Anyone using the 9-pin J1939 port to interface with external devices? if so what kind of devices are you running?
I see there are lots of options available

kjintf · Answer

Looks like I'm on my own for this project

j-d · Answer

Or an automotive/light truck forum like batauto.com

swamp_man · Answer

The OBDII system if for the engine and other vehicle related devices.  I don't know about the 9 pin round connector.  What problems are you having?

kjintf · Answer

Swamp Man

Thanks - I understand the OBDII J1850 VPM protocol via the standard 16 pin connection. I'm looking for what the J1939 protocol supports via the 9 pin connection. From what I understand it's a protocol riding on top the CAN protocol and supports several higher level functions.

Looking for specifically what functions are supported by the Workhorse chassis

As suggested by j-d I moved my question to a heavy truck forum and have received much info

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OBDII & J1939 Diagnostic Interfaces

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