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I assume that the engine cranks but does not start?
There are quite a few things that will cause a no start condition. If you haven't already it would be a good idea to check fuses.
You can also see if you can hear the fuel pump running when the key is first turned on. If you don't hear the pump then it may be the issue or there could be an electrical issue preventing it from running. Often with a bad pump you can pound on the bottom of the tank while a helper cranks the engine and it will run again, a simple test that you might try if you don't hear the pump running. You can also spray some carb cleaner in the throttle body while cranking, if it runs off carb cleaner then you know you have spark and are missing fuel.
Checking for fault codes is normally the first step in no start diagnostics. THis will tell you if the engine controller is awake, and if it is then there will likely be at least one fault code set that will aid in diagnosis. Most things that will cause a loss of spark will set a code, but something like a failed fuel pump will not.
If it has lost only spark then it could be a bad crank sensor, ignition coil, wiring issue, or even the ECM itself.
If you find that it has lost both spark and fuel pressure both and the ECM won't communicate with a scan tool then the ECM would be the most likely cause, assuming fuses are ok.