My Brothers has a 08 Acadia 3.6 the battery wasnt holding a charge so I replaced it, now it wont even try to start. Im thinking it is somthing with the anti thief system, but im lost on what to do.

Everything works, turn the key and nothing happens, one time it attempted to start but shut right off.
ANY thoughts would help greatly.

 

check your connections?

 

What's the battery voltage?

 

have you tried a code reader?

 

connections were good. battery was 13.2 volts. no codes.. took it to the dealer and they had to relearn the ecu.... but its good now. thanks for the help.

 

Ah, so it was turning over but not firing. you didn't mention that part. sometimes you must apply a little fuel with the throttle to get it to fire and keep it running. that will help the ECU relearn

 

was not turning over except one time. and throttle did nothing at all.

 

Interesting