Mileage record in the ECU or the instrument panel

This has been bothering me for a while.

A person i know, is not so honest, has the fuse for his instrument cluster/panel unplug for the sake of nothing else but to disable the speedometer from working. By doing that he is also disabling the speedometer he is preventing the odometer from registering the correct mileage on the digital readout mileage counter. Very dirty, i know and i do not work on his car anymore, because i do not want to be associated with it.

The question here is the mileage controlled by only the instrument cluster or is it also being counted by the ECU? I want to know when he plugs that fuse back the day before he sells it, will the ECU communicate with the instrument cluster to update the mileage count digital display. His car is a Cherokee 2000. I am interested to know about cars with digital displays not mechanical counters in general whether this is a back door for dishonest people? Not directly related to your post kauty, but I read the other day it is easier for the crooks to roll back a digital odometer over the mechanical type.

I subscribe to carfax and constantly run into odometer descrepencies on newer vehicles.
1 in 10 vehicles are tampered with. What hurts the crooks is if someone pulls up a carfax report and see's where it had 70,000 last emmissions test and now mysteriously it has 50,000 miles on it.... the price drops in half. So the crooks are taking a big risk trying to increase the value of a vehicle. It might backfire on him and actually cut the value in half of what it is really worth if he gets caught.

Carfax- Uncovering Odometer Fraud wrote:Interesting article
http://www.carfax.com/car_buying/odometer.cfm


autofacts.ca wrote:autofacts.ca wrote....
Then electronic odometers arrived, driven by a pulse from the VSS (vehicle speed sensor) and a second mileage recorder was secretly hidden in the black box that controlled the transmission.

Odometer rollback and how to spot it
By Phil Bailey
http://www.autofacts.ca/press/article040223.htm


Quote:Odometer software
http://www.tachosoft.com/odometer.htm
I really do not care much if he gets caught because he is old enough (34) to know what he is doing is wrong. I also told him how would he like to have that done to him (I hope it does). Very interesting links.
About the 1 in 10, vehicles are tampered with; i think it is not so much tampering but it is failure to remember mileage when transferring ownership (ignorance/innocence). I personally have had that done to me. my Father-in-law was transferring a car he owned to my wife. When they went to transfer the ownership he couldn't remember the mileage on the car, so in turn gave an estimate, which was less than what it had when it was last reported to the DMV. The car had 88K and he said 60 something K and the car read 88K, odometer was working and everything was right.
A few months later i purchased carfax, because i was shopping for a used car and figured i might check the carfax on my wife's car even though i know her father was the one and only owner because he purchased it new. Guess what it had odometer fraud on the carfax... The more i read into this the more i think it is not possible to alter the mileage just by unplugging the odometer fuse. One would have to hook a device to alter hard coded data.

"Then electronic odometers arrived, driven by a pulse from the VSS (vehicle speed sensor) and a second mileage recorder was secretly hidden in the black box that controlled the transmission."

Deduced answer to my question from Grease monkey's links (Thanks);

"Manufacturers tried to combat these tricks by installing on-board computers that recorded the car's details, including the mileage, which could not easily be altered."Car Repair Talk's forum.