Dash blank new key programming
 

2008 buick lucerne v6
So I lost my key and the locksmith came and cut me a key.And when he hooked machine to my o bdII port it said it was only 1.2v from the battery. However, everything in the car works including the radio, the lights etc. I measured the battery and it measured 12.5 volts.
He kept insisting.Of course, I didn't know what I was talking about but left me the key.And instructions on how to program it. The only thing that lights up on the dash is the check engine light Absolutely nothing else. The fuse is fine. If anybody could please help me.I gotta get this car running.Thank you