Removing remainder of cat heat shield leads to tripping immobilizer?

I took the car back to the shop to address an exhaust rattle after recently having the intermediate pipe replaced due to a leak. They think it's the remaining half of the catalytic converter heat shield causing it (bottom half has previously detached and I removed it). They remove what's left of the heat shield and drive the car to the front for me.



I get in the car and try to put the windows down because it's nice outside - the windows don't work. A closer look at the instrument cluster shows it not lit up.



Something is amiss.



I turn the car off and try turning it back on to see if the weirdness would go away.



Console still doesn't light up and the starter doesn't spin. Lights, locks, and radio all seem to be functioning, though.



Long story short, the immobilizer system was somehow tripped. Fortunately I didn't just take off with the car!



This was near their closing time, so they're gonna work on it in the morning; no idea how this might have happened.



Any ideas? Shy of getting it towed to the dealership, are there ways to reset? The car is equipped with the advanced keyless system, and trying the other key doesn't seem to help. The shop checked fuses, and they seem to be intact. The battery is relatively new and tests good. I've tried lookng up suggestions with paltry results.



Three ECU codes were reported :



U0155 - Lost communication with instrument panel cluster (IPC) control module

U0167 - Lost communication with vehicle immobilizer control module

U02xx (I forget this last one) - Lost communication with ...