Fix U0401 Code Invalid data received problem from ECM/PCM

My 2004 renovation is coming along well. Engine runs great but she has a list of DTC codes that would likely prevent me from passing state inspection and getting a rebuilt title. Gauge cluster is coming out to get rebuilt and fingers crossed that clears the U1000 code for the IPC. I also found out why the SDM module was throwing a U1000 too - it was basically reduced to a pile of oxidation under the drivers seat. There is water on the floor of passenger side. Is that coming from the sunroof, or