So you have a controller (#1) trying to send a message when there is no other controller on the bus. CANSTS contains a 0x43 which is what CANStatusGet returns. Now you turn on another controller (#2), the message is sent out of #1 and now CANSTS contains 0x48, or CAN_STATUS_EWARN | CAN_STATUS_OK.
It seems once EWARN is set, it is always set. How do you clear it? Is there a reason not to clear it?
I am working with a TM4C123BE6PZ using CCS 5.5, TivaLib 2.1.