Question on Milage stored in Computer

[JayChou]

I was told that the actual milage of the car can be traced from the computer, so that people can't do tricks on the Odometer (the mechanical one).
But some cars are now equiped with digital odometer, and I believe that they are getting data from the computer. So, how am I going to trust the number displayed on a digital odometer if that car has a aftermarket computer?

[deltafox]

Ive not heard of the mileage being stored in the "computer", rather its stored in the instrument pod ecu.
That may have changed recently though with he introduction of ever more advanced engine management systems.

[JayChou]

so if that concerned part is changed/ replaced, there's no trace of the actual milage?

[Mr Jenks]

The majority of modern systems using multiplex technology stores mileage in one or more ecu`s. If any one is changed then the highest mileage recorded is transmitted to, and stored by all the others. No more substituting components in place of correct diagnosis.

[annodomini2]

Mr Jenks said:

The majority of modern systems using multiplex technology stores mileage in one or more ecu`s. If any one is changed then the highest mileage recorded is transmitted to, and stored by all the others. No more substituting components in place of correct diagnosis.

Assuming the systems are compatible.

[360 stradale]

Even some cars before multiplex have a similar feature. For example, if you have a 355 with F1 the mileage is stored from the day it left the factory. Renewing every e.c.u on a modern car to hide the mileage would financialy outweigh any benefits of clocking the mileage....

[annodomini2]

Unless you know the codes to change them all!

All systems have a fairly secure configuration for this function and its generally unique to at least the manufacturer if not the system.

[Mr Whippy]

Reference the MOT certs and documentation. Make sure it all tallies up.

No way to be 100% sure what that little clock says in the dials.

Dave