Digital dashboard for Harley

Do you know how this data should be interpreted? Which part of the line is the address/id, and which is the data?

I studied the description of the j1850vpw protocol.
The first three bytes are header.

  • The first byte of the header is information about the priority of the message, IFR, addressing mode, message type.
  • The second byte is the recipient’s address.
  • The third byte is the address of the message sender.
  • Starting from the fourth byte, payload data is transmitted. However, it is not entirely clear what information the 4th byte carries.

For example:
A8 49 10 10 3E 50
This is the engine temperature(taken from HarleyDroid). We take the value of the 5th byte. This is the temperature data from the sensor.
Another example:
28 1B 10 02 00 00 D5 - RPM
Information about the rotation speed is contained in bytes 5 and 6.

I think it might be possible to use the first three bytes as an identifier. They are unique

I have to think and study this a bit. I does not fit into CAN adapter connections as only one that would be capable of reading this would be OBD2 adapters.

But this protocol should be readable with OBD2 connection type by polling the values with ELM327 commands?

Thanks for your time, dear dev!

In theory a vehicle with j1850vpw data bus should respond to standard PID requests. I had no experience communicating with the ECU of other machines using j1850vpw. I guess Harley Davidson engineers took liberties when using the above protocol for data transfer and did not use standard pids. For any request of standard PID from a motorcycle, I receive NO DATA in terminal. I really have no idea how to get the PID that is used in HD. That is why I think that the ATMA method is the only one that can give results.

Maybe it is possible to sniff outgoing traffic from the Harley software to find out the pids used, but I do not have access to this wonderful program :sob:

I think best solution would be to create new connection type for Harley J1850VPW as this does not really fit well to any existing connection type.

That would be great!
I will do my best to develop an xml description file that will expand the range of vehicles that RD is friends with.
Don’t think I’m arrogant, but when can we expect a release with a new type of connection?

I’m testing it right now on the simulator. So it will be in next release, planned for next week.

As I have no way to test it on real hardware, I will mark it as untested for the release.


I am ready to help with testing on a motorcycle if necessary.

Send me an email to if you’d like to test pre-release version.

I’m going to dump a known harley diagnostic software and see what pids i can find for you guys :slight_smile:


Im assuming this died here? We never got a working solution for Harley davidson?

Yes we got. The connection type in RealDash is named ‘Harley Davidson J1850VPW’.

Is there an xml available for it?

No need for XML, connection is hard-coded into connection type.