2012 Dodge Durango P0001 U0001 B0001 C0001 Error After Head Gasket Repair - How to Diagnose and Fix

I recently replaced the head gasket on my 2012 Dodge Durango after a blown gasket. The shop repaired the dual overhead cam timing system, which required extensive disassembly—very time-consuming but successful. After reassembly, all timing-related codes disappeared. However, I now have persistent diagnostic trouble codes: P0001 (Intake Air Temperature Sensor Circuit Malfunction), U0001 (Communication Error in Powertrain Control Module), B0001 (Fuel System Pressure Sensor Circuit Issue), and C0001 (Catalytic Converter Efficiency Below Threshold). I've tried resetting the system multiple times, but these codes return. As a hotrodder from the 60s/70s era, I'm struggling to understand modern engine diagnostics. These codes are likely related to sensor or communication issues in the ECU. I need clear guidance on how to troubleshoot and resolve them without damaging the vehicle's electronic systems. Any advice for someone with limited experience in modern engine tech would be greatly appreciated.