Service trac and service Esc. ABS,BRAKE and traction lights on. Code C0550 . Took to shop and were not able to diagnose problem. Glitz in computer??
DTC C0550 = Internal Fault/Electronic Brake Control Module.
Based on @Testers reply, I’d be looking for a new shop to work on this as the one you have doesn’t seem so good…
this is interesting, I worked on a friends car last Friday that did a very similar thing- his is a 2008 HHR.
His Service ESC light came and caused some sort of limp mode. Car would hardly run. He had different codes than yours though.
Searching online for a solution, kept coming back with check tire air pressures. Many folks said a tire or two 5psi off of the others will cause the Service ESC to come on- his LF was 5 psi low.
After getting that adjusted (and not sure why this is an issue in a non-AWD vehicle,) his ABS/Brake light is on now. I think his regular mechanic suggested a ABS brake controller.
so, based on my experience, and your code:
Check the tire pressures and replace the ABS Controller, lol