Don't hold me to it....been awhile since I worked on them for a livin'......but, and this is Dodge I'm talkin' about....Yes the ecu does track mileage and is/ was I should say, installed with a program with specific info for that vehicle.
Good question and I'm sure the bean counters thought about it ........consumer gettin' around the warrranty etc. comes to mind

 

I too though the ECU contained the car's mileage . . . .

 

maybe in the BCU?

 

It was discussed on here back in the spring, and there was a copy of a service bulletin from GM on how to tell if the programming had been modified or the computer switched. I don't think most dealers will be looking that hard, but they can if they want. The problem is that any service work on the program is listed with them and there are check bits like things in the program that have to match up with what was last supposed to be in there. Rather than buy a spare computer(expensive), why not just get HP programmer setup, or others, and you can switch stock from custom when you want. SInce they can know either way, why spend the money on the computer?

PS: Some programs retain mileage in the ECM, BUT its for reference, the ACTUAL car mileage that reads on the dash is on a chip in the dash display. It would be to easy to change if it was in the ecm.

 

I ended up buying a spare ECM for the SS, and since I now have the BSR tune, haven't decided whether or not if I will keep it or sell it......
sometimes having a spare is a good thing.........

 

fwiw... many new cars hold their odometer readings in the dash, separated from the pcm...

several people have a separate pcm to swap back in case they have an unfriendly dealer... and our pcm's hold the automatic tranny shift learn - everything else is put back to default...

like i said... fwiw...

 

If you buy a new ECM it will still need to be set up by a dealer. Yes this would work. There is almost no way to tell when an ECM has been replaced unless the person replacing it is sloppy. However a dealer employee could check the production number on the ECM and verify that it is the same as what shows on the build information. Highly unlikely this would ever happen unless there was cause to invesigate such as a powertrain failure. Most dealer employees don't even know this information is available.

I have not seen or heard of a tune causing a powertrain failure in an ecotec. The big problem is the diesels. And I have seen lot's of warranty denials and warranties voided on them.

You would want to tune the 2nd ECM and leave the original alone.

Also correct on the cluster holds the miles or on some models (not the HHR) the tech sets the miles during programming of a new cluster.

 

could you take an ECM straight to a dealer and have them program it? Or how would you go about doing this? possible to do on your own?

i.e. buy an extra ECM, and put a Hahn tune on it...what would be required to the ECM?

How much do they cost?

 

Dealer would need the vehicle to set it up and a HAHN tune will not work on a unprogrammed ECM. So the problem is explaining to the dealer why you want a new ECM and to have it programmed.

SSRoadster should know cost.