DTC U0121 x 4. "4 modules not communicating to EBCM"

Did you ever find resolution to your issue? I hit a raised speed bump in a parking lot and now have a bunch of Non-Comm codes to the ABS module and ABS/SKID lights with a Service Power Steering message/chime upon car start. Also have the dead battery symptom since the car sits.

I have been driving around with this problem for 3 years - ever since the dealer didn’t mention anything about the TWO TSBs that might explain this problem from just a wiring harness and/or connector corrosion problem. They went straight to the $2000 module and didn’t sound very confident that would solve it. So I don’t know what to do and have been hoping that someone else somewhere online would post a solution. I can’t afford to throw away $2k and just hope there a chance it works.

I will check on the TSBs This car spent most of its life in FL, TN, and TX, and has slightly more body issues than it does corrosion.