I don't need an engine ECU (knock on burl walnut!) but I was curious about the mileage on the odometer - I thought it was stored in that engine ecu / ecm.

If replaced, would the car now have a different reading for its mileage?

Could not find anything on that in past posts.

This is regards to the XJ6 X300 95-97 in North America.
Thanks

 

It's stored in the instrument cluster.