2013 malibu 2.5 not starting

[bennuss]

I was getting all kinds of weird stuff including codes u0100, u0422. tested to be a bad battery . i changed it but i was given a 47a instead of a 47agm .
Not sure it its a difference. Do I need to change?
Now it wont start. i tried boosting it with my LiON booster and nothing. I did get someone to start it but he had one of the old type of lead based boosters. I let it run for an hour. Today it wont start .
When it wont start I dont even get a crank but I do have lights.
Is it the wrong battery or something else. I cleaned off the wire ends and put on di-electric grease.
what else should I check?
thanks

[aleekat]

You need a voltmeter to test the battery. Should be above 12v static. If you try and start volts need to stay above 9-10v. Anything less probably bad battery. I would take the battery back and have it load tested.

[bennuss]

I had the battery tested. tested good at 12.6v fully charged. Any ideas. what to look at? I checked every fuse. except the ones under the dashboard.
Update. after testing the battery. i put it back in and wriggled the negative cable and it started but it said
service power steering
service stability
and the tach didnt move and the I had no speedometer.
I backed it into my driveway and then pulled forward. when i tried to go back i had no reverse.
Any ideas? Bad negative ground cable? Bad PCM or BCM?

[aleekat]

Poor grounds can cause all types of symptoms. Fix that ground cable and see what happens.

[bennuss]

I changed the ground cable. Still randomly not starting. And when it doesnt start its zero response . Also shows on them menu screen
Service Power steering
Service Stability trac
Which seems to imply a bad ground but which?
Should I change the PCM ? BCM how do i know which one?