I have an 05 S40.. When turning or hitting bump would lose power momentarily. After, if I shut down and tried to restart...nothing.. Leave key in on position car would start weird error messages, clicking in many areas, then reset and allow to crank... It got to the point when I turn corner would lose power momentarily every time. I came to stop engine died then no power anywhere.. No power to door locks, lights, anything.. Hot battery but no power... Any thoughts? I am thinking a short to alarm system?

 

not sure if I'd blame the alarm system as a first thought. I'd check the ignition switch...

 

Should be relatively easy to find the problem (as long as it "stays broken"). Just use a voltmeter to start tracing the 12 volts from the battery to / through the fusebox. The problem is where there's 12 volts on one side of "something" and not on the other. Given the symptoms, I'm betting it's a cable / loose connection (where gravity would slightly wiggle the connection enough to make/break it). Another quickie troubleshooting trick for a totally dead car is to turn on the lights and/or wipers (and the key) and start wiggling cables until you find one that causes the lights and/or wipers to come on/off. The issue should be obvious at that point.