Pontiac Repair: G6 wont start, battery cables, car wont start

Question
i have a 2008 Pontiac G6 i think the engine is 2.5 , well my car wont start i thought it was the battery but its not i got it tested in a auto part then i get home and the car wont start again . a mechanic came and told me it was the key program but its not. the locksmith said is the computer because on the dash it says ERROR every time i try to start the car..please help

Answer
Hi there:

weel first thing to check is the battery cables. I have see battery cables break off at the engine the black (-) cable on the transmission. if not that then one of the modules has gone bad in the car and it has taken down the communication line. all the computers in the car are linked together and if one of them is sending out corrupt info or has gone bad the communication between the modules basically shuts down and then that car wil not crank/start that is why the odometer reads error. It's not receiving the proper info to display the milage. If the ground wire broke off it will effect the modules in is a similar way. good luck :-}