Running fine, very brief stop, car won't start, jump, starts fine since...

I need some help from the gurus sorting out what could possibly be the problem on my 2001 Jetta TDI with 205k. My car was running well today when I stopped it for about 30 seconds to get my mail. When I tried to restart, all the dash lights turned on, but the engine barely cranked, sounding like it had a low battery. Over an hour, I attempted to restart it multiple times with no luck. A few hours later, a friend gave me a jump, and immediately the engine fired up without any trouble. Since this occurred, my car has been starting fine. Any idea what caused that, and what I need to fix to prevent this problem in the future?

Don't know the answer to your problem but I can tell you my 2006 jetta has been doing the same thing for a couple weeks now. The battery fails when the car is ran for awhile or when underhood temperatures are high. I noticed that my AC fan doesn't work but I learned on this site that that is a common problem on 2006s. I have the fan and I will see if that helps. I am curious as to what people on here will say... Subscribed

I would have your alternator checked.

my 0.02-
Start by checking the big battery cable connections- at BOTH ends. That is, check the battery post connections, and also check the connection of the ground cable under the car, and the fat + cable at the starter solenoid. Make sure they are tight and corrosion free.

Next, the battery itself is not beyond suspicion. Sometimes they can develop a loose plate inside which can be intermittent. It's not highly common, but not unheard of.

I think if the alternator was not charging, you'd have a red light on the dash...

Best of luck !!