I was car shopping online for a Cadillac CTS, preferably low mileage, and a few years old. I found one, a 2004 with 27,000 km (16,740 miles). I thought I had lucked out. My father in law has a car dealership in the same city as the dealer with the CTS so I called him to see if he would check out the car for me. I told him the dealers name and the first thing he asked me was if the car was bought at a dealer auction in Quebec. I asked why and he told me in Quebec it is not illegal to alter odometers and this car's mileage was unusually low ! The FIL says that digital odometers can be "flashed" to change the reading. I did not know that was possible. I called the dealership with the CTS and asked where they got the car. The slimy salesman knew what I was getting at and said he had no idea where the car came from. He had previously told me it came from an online auction! Also there is no VIN showing on the online ad, so I can't get a carfax report for it or get a friend at a GM dealership to check the service records. Needless to say, I am passing on this "low mileage" car. Have any of you ever heard of this? Buyer beware!

With the LS based trucks I have seen inaccurate mileage on clusters do to folks like myself swapping out the crappy Sierra stock gauges for Cadillac Escalade gauges but here we are required to either put a sticker on the car and document that its not the actual mileage or to have the cluster programmed to reflect actual mileage.

BUT as I understand it the actual mileage is held in the PCM and even with a reflash still holds. Mine has been tuned and update a few times and mileage is correct. Maybe someone with PCM programming knowledge can clue us in on specifics but as I understand it the PCM holds correct mileage even if the cluster is not correct / programmed to reflect actual mileage.

Maybe you could test drive and have your buddy plug in and see what the PCM reads?

the reg. of motor veh. can tell you the if the miles are real or not..
when it got a safty/immission sticker they punch in the miles into the computer...
so everytime it gets a sticker(yearly here) the reg. of motor veh. gets a milage readout..

If you FIL is in the same city as this dealership why not ask him to go over and pull the vin in person?

Acutal mileage in the PCM? I don't know about that. I have reflashed my PCM myself via HPtuners and even swapped PCM's. The real PITA is that the late model truck clusters are not servicable...Yopu can't even replace the dash light bulbs yourself. I need 2 replaced in mine but I hate to spend $100 on it just for that.

The 1994 Impala SS I owned had digital odometer that would rarely display the correct mileage (cluster contacts were corroded on the circuit board I was told by other Impala SS owners). The Carfax report said "possible odometer fraud" as on previous smog checks the mileage was recorded incorrectly due to the digital odometer reading incorrectly at the time of smog. The used car dealer that I bought the car from sold it as a car with 124,000 miles (and the car showed wear for those high miles). I swapped in a '93-'96 Camaro Z28 cluster and set the miles at 500 miles more than what the digital odometer claimed (I had driven some miles without reflashing the computer for a rear-end gear change). When I sold the car (with 167,000 miles on it), I informed the buyer of all this, plus checked the "odometer mileage incorrect" box on the title (because the milage was close, but not exact). The buyer was cool with it. I had nothing to hide. But, dealers (not all!) on the other hand, like to be dishonest, which is not right. I'd be passing on that car, as it looks like you already did.

why not look at the car first, and then decide if it's a good deal for the amount of money they are asking for it. if it seems worth it, then get it. if not, don't.
it really is that easy.
mileage is just a number- i've owned cars that were all but dead by 80,000 miles, and i've had cars that were almost as good as new with over 200,000 miles.