Well, I change my old Ecu, with a new ecu. (Old one locked) with anther model. I have GMC truck Silverado & I make replacement with Holden Commodore 2002 I take it from junk, I make all changed and gone fine just 4 things. A/C not works at all, fuel gauge not work, battery light not close well battery gauge good read, speedometer move but run quickly.