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Power from ODB2

Is there an interface to extract the power and CAN bus from a car's ODB2 port to a microprocessor? One problem I am worried about is the microprocessor draining the car's battery when the car is off. 

 

Thanks,

Michael

  • Michael,

    This will also be OEM specific.  I'm not sure if power is routed to OBD2 port.  The OBD2 tools I know run on their own power (either battery and handheld or a larger tool that is plugged into the wall).  CAN is definately routed to OBD2 as it is an international norm for diagnostics of OBD2.  Since the OEMs all choose to route various signals and capability to the OBD2 port in addition to the internation govenment mandated minimums it is hard to tell what may or may not be available.  The information I know about them is all NDA with the respective OEMs. 

    - Scott

  • Scott,

    There are some OEM specific pins for OBD2, but to my understanding, there seems to be a standard set that includes CAN and 12V from the battery. We will probably use a load switch to disconnect the battery when the car is off - is there a signal coming from the ODB2 that will determine when the car is on or off?

      

  • I don't know.  I'm not an OBD2 connector expert, the OEMs own the port. Base on the chart you gave above there is no igniation controlled 12V but it seems several pins are undocumented or un-used.

    - Scott