Fix for several engine codes?

[Dano11]

Hey guys. Can you help me fix some codes on my G37?
U1001 CAN Communication Circuit Fault
P0603 ECM Back Up/ Circuit
P1090 VVEL Actuator Motor B1

Thank you!

[mdmellott]

This is why I hate CAN bus systems in modern vehicles. All of these seemingly unrelated symptoms are interconnected by a network of components that share a common ground and data messaging between some of the components and the the vehicles various control modules. Finding a loose or corroded component harness connection or battery terminal connection is my only hope to find the root cause. Otherwise, it takes more complex diagnostic tools from dealerships with vehicle specific software programs to pinpoint the problem.

[Dano11]

Thank you! I will do my best