OBD-II synchronization errors RaceChronoPro V3.00

Sorry I missed the window to send this out during the beta test. I was just running RCP while driving around town today and encountered what I only can attribute to a serious error in synchronizing the OBD-II stream.

While logging (without video) and driving, I suddenly was presented with dashboard failure lights for traction control, brakes, and tire pressure. Shortly after the EMS (emission management system) light lit as well and the car went into limp home mode. Pulling off the roadway and stopping RCP, I launched another diagnostic program (DashCommand) to look for OBD-II fault codes -- there were none. Shutting off the ignition and restarting the car reset all the failure indicators and the car once again operated normally.

I had been running with the "log OBD-II data" option enabled, and I looked at the file device_output_3.obd. There were many "< DATA ERROR" responses from the OBD port, as well as several "> BUS ERROR" responses. It appears that this file only shows the output from the port, and not the commands sent down to the port, correct?

Here is the environment I'm working with:
US BMW 2005 M3 (MSS54 ECU)
Nexus 5 phone, Android 4.4.2
OBDLink MX bluetooth adaptor

I have used other logging programs such as DashCommand and Harry's lap timer successfully with this hardware without an error such as this one, so I'm pretty sure my configuration works. I wanted to use RCP because of the ease of exporting the logged data for post processing on my desktop PC.

If you need more information let me know, I'll be happy to try to help. Perhaps it would be useful to add some advanced configuration parameters to OBD-II port handling such as a settable inter-command delay.

Thanks for any help you can give!


  • aolaol
    edited May 2014
    Hi Paul,

    This is not RaceChrono Pro problem specifically as the RaceChrono has identical OBD-II support. The commands sent are not visible in the log, but RaceChrono merely requests OBD-II PIDs and never writes or clears anything in the ECU. Sounds like it is a OBDLink MX related problem or an intermittent problem with the car. Let's continue in email, as I think we have to contact OBDLink MX support.

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