I know too, did the same thing ! Ouch !!!If you have to access your battery DO NOT remove the four bolts that hold the ECM to the plastic plate on top of the battery.
There is one bolt at the rear of the plate. Remove that and slide the plate forward with the ECM still attached. Then you can swing the assembly up and out of the way.
If you remove the ECM first and then remove the plastic plate there is a strong possibility that the ECM will slip and fall onto the pos. battery terminal.
Zap! Just like that, there goes $600. Trust me. I know.