2008 Vibe not starting after disconnecting battery & re-learning

[Bchappell]

Hi friends!
New to this group but in need of assistance because I'm super confused!
So my 2008 Vibe was running fine until a few days ago when I had to change my headlight and I disconnected the battery. I re-connected everything and the car started up fine but was idling heavy, which I expected because I've encountered the computer relearn issue before. I got to where I was going and spent a couple hours there. Left and the car started up fine. Went to a restaurant and after a couple more hours got in the car and it started fine. However, the next day when I went to leave, the car didn't start. The dash lights didn't turn on and the car didn't even try to turn over. I jumped the car and let it run a few minutes but once I shut it off it didn't start again. However this time if I turned the key to the on position, the dash did light up. I jumped it again and attempted to drive it to the store but it was idling super heavy and it stalled out at the first red light when I turned off the AC and the rpm went from around 750 to basically nothing. So I jumped it at the light and got it back home. I found some info online about how to get the car to re-learn the programming. I disconnected the negative battery terminal and cleaned off some minor corrosion that was on it and reconnected everything after about 20min and made sure it was on tight. I went through the steps of "reprogramming/teaching" the computer and it went from idling heavy to then idling as normal. I shut the car off twice and turned it back on with no issues. The next morning it cranked up just fine for me to go to work and I thought the issue was fixed. However, several hours later when leaving work it no longer wanted to start up. The dash lit up and it gave some minor power, but it didn't even crank when I turned the key, let alone begin to turn over. I jumped it again and got it home but now I am at a standstill of not knowing what to try next. The battery is only 2-3mo old. The car has 295k miles on it. Any help or suggestions would be super appreciated!!

[SSizler]

Welcome to the site!
The fact that you can jump it and get it going again for a short period tells me you have a bad battery or something in the charging circuit is not working properly.
Cleaning the terminals is good.
How do the battery cables look?
Do you see or feel any bulges or weak spots?
Could be a battery cable is going bad.
You removed it from the battery then moved the cable around - that is a change.
Also, a new battery can go bad fairly quickly, even within hours.
I would fully charge the battery overnight then take it to a place where they can check your charging system, unless you have a meter and are comfortable checking electrical things.
Battery voltage should be around 13vdc before starting, will drop after starting, then go back up after the alternator does its thing,
If voltage does not go back up and maintain 13-14vdc while running you have a bad alternator or voltage regulator (the regulator is in the alternator), or some kind of impedance that is not allowing the battery to charge.
My first guess is it's the battery cable or battery.
Keep us updated on your progress.

[andrewclaus]

Ditto all the above.