Hi guys. Non boat related question. I was headed out to look at /purchase a diesel truck and CarFax came back with possible odometer fraud. I have searched and searched, is this stored in the ECM like hours on a boat? I believe the seller and the odometer when they purchased the truck was consistant with millage.

as sydwayz said it depends on the truck. I repair ALOT of GM clusters and the ones from 2001 to around 2006 are stored in the cluster but around 06-07 they started changing the programs and the millage is stored in the ecm. the early one the ecm will have its millage and the cluster will have its millage. they dont talk to one another so if you put a different cluster in it will read what ever it had and will be different than the ecm. on the later ones the cluster just parrots the ecm and after a few seconds will change millage to what is in the ecm. all brands do this in different ways so it is possible the cluster or the ecm was changed out at some point.

I bought a truck with a carfax that said same thing....turns out in my case they were going off of one of the emissions mileage readings that im sure some lazy kid didn't properly enter in properly....the mileage on the test before the discrepancy was at 65,000 then there was a reading of 8,000....then the next reading was 101,000 so i didn't have any issues buying the truck since the mileage still made sense to me at the time.