I got a new bcm to replace the damage one but the one I got was used so it couldn't be program than I got a new one and now the miles are reading the used bcm miles anyway to fix that

 

Sounds like something a dealer should be able to take care of easy, or best case maybe a GM tech2.

 

The dealer says there not authorized to do that

 

I don't think they can change miles in a used one; only brand new ones.

 

That's what I was meaning. They should be able to change the new one that OP bought.

 

He even states in the OP he bought a used bcm.

 

but then he said "than (sic) i got a new one"

 

New to him.

"Got a new bcm and its reading the old cars miles"

Aka. Used bcm. Lol.

 

wow, ok. i have a hard time with poorly constructed sentences.

 

I'm with you exninja lol

 

Sorry for bad grammar bought use one! Couldn't be programmed so bought new one got it programmed reads old bcm miles from used one not original miles

 

BCMs bond for life. Once programmed to a vehicle, they cannot be programmed to a different vehicle. With our cars, you have to actually disconnect the ipc and then use tis2web to program it and set up vin, mileage, and sdm identification. But that can only be done with a new one, one its programmed once, thats it.

 

tell who ever is trying to program it to disconnect the ipc and reprogram otherwise the bcm will self populate miles based on ipc input. If its a dealer, tell them to look up document id#2074175