I have a 1999 Interstate and recently it started resetting the odometer sometimes.
The trip odometers will reset to zero and the display will be on the total miles.
Would the odometer reset if the battery was disconnected?
This is exactly what happens when power lost. Trip setting is lost, and the odometer mileage is back.
But it's an IS model, so how is your radio, do you lose the presets? This, I think, takes a little longer, put I would need to check this out by removing the power lead from the battery and connect again to verify.