I'm not that familiar with the newer models, but I'll assume it has a fuel shut off solenoid. If that is the case, then losing power to the ignition switch would cause it to shut down.
The first thing I would check, would be the circuit breaker, going to the ignition switch. Here is a link to the Case Construction online parts catalog, for the 580E, that shows a bank of circuit breakers.
Official Case Construction Equipment Online Parts Store and Parts Look Up. Parts for Case Equipment and Construction Equipment. Parts Store for Case Wheel Loaders, Case Excavators, Case Skid Steers, Case Original Parts. There appear to be 5 of them. You can do a continuity test from the ignition switch, to the proper circuit breaker. Once you find it, check the circuit breaker, to see if you have power going through it.
If you find that the circuit breaker is bad, remove, and take to a local auto parts store, and match it up with the correct style and amperage. They will be 1/4 the cost, versus going through Case. Auto parts store price will be approx. $7.00. Case price will be approx. $26.00.
I had the same problem with my 480C, not having power to the ignition switch, although it has a manual shut off. The PO had rigged a remote starter switch on it, which I wanted rid of, and clean that mess up. With the help of the service manual, I traced the wiring to a circuit breaker, going to the ignition switch, that was bad. Replaced it, and it fired right up.
If you don't have an OEM shop manual for it, I'd highly suggest getting one. They are very informative, and take you though repair procedures step by step, with lots of photos, which are a great help. I found mine on Ebay, for right at $100. Best money I ever spent.
It's easy to get overwhelmed by some wiring diagrams. Best thing to do, is set there and look at it for a while, and just trace the circuit you are looking for, from point A, to point B. All wiring harnesses are color coded so they are easy to trace, either by a solid color, or color, with a colored stripe on the insulation. If I remember correctly, the Case manual, at least on mine has a list of the color of wires, and what they go to.
I don't know if that is your problem, but at least, it is a place to start.
