Going back through posts I may have missed a reference, but if you have no readings at the O2 sensor, have you checked the OVP? If the fuse on top is blown, or the relay is bad, you will have no power to the ECU. Usually I think the ABS lite is on, but maybe not if you have the 2-fuse model.
Also, it is possible you won't have ECU functions if another input sensor - such as crank position, airflow, etc, were malfunctioning. I wouldn't assume the ECU is bad, under the circumstances you indicate.