Went back and looked over the prior posts. My HHR does not have OnStar or Sirius. There is no VCIM under the cargo panels. Have removed all on right side. Nothing there. So from reading maybe my problem is the BCM?

 

What happened just before the car started this problem?
Those U codes lead to a bad connection on the ECM or the EBCM. Has anyone pulled the ECM plugs or the ABS "brain"?
The EBCM (ABS brain) is the module with the brake lines on it.
The way the network works is if a module gets disconnected by either a loss of power or loss of connection to the network all of the modules "downstream" get disconnected.

I posted a vid in #2 about finding which module has a problem.
You could try disconnecting each module and inspecting the pins.
Check all of the fuses on both fuse boxes.

 

Reread my post #6 , start with the simple stuff.

 

OK, now we’re on:
U0073 Controller Area Network (CAN) Bus Communication
U2108 Lost Communications With ABS/TCS Control System
U2111 Lost Communications With Steering Control System

A bad battery will do that kind of stuff. Go back and read my comment #7.