2004 V40 turned off ignition and all power died
 

Just bought 2004 V40 for my girlfriend the other day, today got home and turned it off. The radiator fan continued to run for a couple seconds then all power went out. No interior lights, door locks etc... Car is as if the battery is not in it. Checked battery and it is good and has good connections. Did multiple searches and read through the FAQ section. Cannot find anything relating to this. Any help would be greatly appreciated.

So when you try to restart you get nothing? I would recheck your battery connects first. Take the battery right out and reconnect making sure both terminals are in nice and solid. Then maybe have a look at all the relevant fuses? If that yields nothing I think you may be into some continuity tracing from the battery to the next component inline...I wonder if your CEM might be fried?

Thinking about this further I think you should take your battery in for a proper test assuming no issues with fuses come to light

Had battery on charger and said good. Took to Autozone and tested good. Put back in and still nothing. Took out and got new battery, figured bite the bullet since I'm in Las Vegas and its 110 plus this week, and it worked. Figure I had a bad cell but don't know why autozone said it was good. So now its fixed.

Thanks for the replies tho.

Glad it was a simple (relatively inexpensive) fix.

I may have had the same problem with my 2001 V40, it seems very similar to what you've described. A new battery fixed my issues too (I'm pretty sure it wasn't just the battery that was the issue though, there's probably a root cause but a replacement battery gets things going). If you have the issue again here's what I do that seems to fix it every time. Remove one of the battery terminals and while you're sitting in the drivers seat with the key in the ignition have someone lightly touch the lead to the terminal. For me this has always caused the dashboard lights to come on but if it's fully connected the same problem you described would happen again. With the lead lightly touching and dashlights on you may be able to start the car and from there the battery lead can be secured and in my case the car then works consistently for another few weeks. It may not work for your case, and it's certainly not ideal, but you could keep that in mind for if the problem happens again.