hmm, i doubt the YJ gauges are that smart, would require some sort of non-volatile memory or counter and i can't see how that would actually work otherwise with the mechanical odometer.
i've never seen that light btw, but mine did not reach that number of miles yet (82,500mi or 132,000km)
did you try resetting the computer?
I'll try and have a look in the FSM to see if there's anything mentioned in there