I have a code that says my #4 injecter cycle open, misfire. on 2005 Dodge Neon

I switched the injector and with the key on and the fuel rail out. It keeps spraying fuel out of # 4 injector. Since it's not the injector on #4, is there a chance it's the ECM that is the problem.

Asked by for the 2005 Dodge Neon
maybe...or maybe you have a wiring problem
Injector doesn't stop spraying. What kind of wiring problem can I check into myself, between #4 and ecm. Will a dealer scanner tell me about a wiring problem or a bad ecm?
Ok, what kind of scan tool do you have, like a Snap-On Modis?
I checked tonite and the injector plug has constant power to the injector. Not good. I just used a Advanced Auto scanned, the code is PO204. With a Snap On scanner what else can he look for beside the PO204 code?