Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
It sounds like the PCM connector is loose of corroded and tripping it into fail-safe mode.
Do you plan to fix this yourself?
Did you put it back together with dielectric grease?
Does the tach work?
Also check for signs of damage to any of the wires all the way back from the PCM as far as you can trace. These three codes are all communication codes with the PCM. Unless you have other codes stored also then I would say it has to be a connection issue.
Let me know if you still need help on this. Please don't forget to rate.
Ok. I just didn't want the question to drop to my timed out list. Rating doesn't close the question, by the way. I'll be here to help as long as you need.