2001 LC stalls after jump starting

[lxdor]

Greetings from Portland Oregon.

So I got back from a 3 weeks trip from overseas, and my 2001 LC won't start. Jump-started it and left it running for 15 minutes. When I put in reverse gear it lost all power and stalled. Jumped second time and realized head-light was dim. Used voltmeter and found battery is measured at 9volts. Took out the battery and charged at friend's place and it hold charge after overnight. Took out the alternator (serpentine belt looks good). Tested at local autozone and it passed the test.

What else can I check? Any advice is greatly appreciated.

 

[mobi-arc]

Might need a new battery. ECU may need to re-learn how to idle after low or no system voltage.

 

[lxdor]

Thanks for suggestion. I am leaning toward battery also although I haven't had a chance to test it at a shop. Two more question:
1. What's ECU re-learn? how to do that?
2. Does it make sense to make old Toyota original alternator in now I have tested it to be good? Or buy a re-man one for $150?

 

[Trunk Monkey]

The ECU will remap while the truck runs and after a few times turning the truck on and off. During this time the idle may be high or low. It's nothing you have to "do" to the truck, it's just a time driving/running thing.