In which city was your vehicle located? As others have said, thoroughly rinse with clean water, ensuring that all areas, including the frame, are covered. Next, a thorough application of cavity wax. Remove liquids and remove floor coverings. There is no need for excessive concern over the ECU's located beneath the passenger seat, since they can be readily supplied at a low cost. My knowledge of the engine Electronic Control Unit (ECU) is limited. Based on the waterline, I believe you will be safe.