I have a 2003 Volkswagon Passat. I left the lights on all day so that the battery was entirely dead. The next day I got a friend to help me jump it. He put the cables on wrong and when we put them on the right way, the car wouldn't start. I had it towed to mechanic. They said they didn't know exactly what was damaged but the ECM was probably blown. They also said the electricity was running backwards and even if the ECM was replaced, all electric systems would start failing in a domino effect. They also called a local dealership to verify this. I assumed a car from 2003 would have fuses to prevent totaling your car by connecting jumper cables wrong but the mechanic said otherwise. Is there any reason I shouldn't call it a loss and junk the car?