Will not crank

Make sure battery has a full charge and connections all good, positive and negative battery connections. Cranking is starter motor action, your saying the starter motor won't crank the engine? Usually two voltage circuits at the starter motor, one is hot all the time, comes from battery. The other circuit goes hot with key in the crank position and is wired through neutral switch for automatic. Haven't looked at your wiring diagram. Now if your saying it cranks good but won't start, that's a different issue. Check for spark at the plugs, proper fuel pressure, fuel injector pulse. You may need to check cylinder compression? Any applicable trouble codes?

Just to add, starter motor is grounded through engine block, something to check.

Everything is turning over, just not firing. Starter is good.

Just to be clear on nomenclature, "cranking" is the starter motor engaging, if that is not happening check the ignition and starter circuits, especially the battery cables to the starter motor. If it cranks, but doesn't fire (engine runs), then it can be a host of things. Check the crank sensor is hooked up properly. May want to crank it while hooked to a scan tool that can go through the ignition step by step, and see if there is a missing sensor input preventing it from cranking.

Sorry I started my answer above before any earlier replies had posted, not trying to reiterate the same replies.