a very common problem in the 05 - 06 vettes with the telescoping steering column is the connector for the steering wheel position sensor dtc C0710. GM's fix is a plasic clip that holds the terminals in the connector. part number 19179794. Now cause you dont have a tech 2 help diag this. Try unpluging the connector and pluging it back in a few times with the car off. Make sure the steering column doesnt move and road test the car to see if the light comes back on.
And now after writing all this, i just realize that you have a abs light not just a tcs/ah light. the steering wheel position sensor will not cause the abs light to come on.
Now on to my next guess
Lets start with the basics, check the battery cables and the over all heath of the battery.
GM has a bulletin out for false abs codes. check grounds g106 in the engine compartment, RR of the right side cylinder head above the starter solenoid, and g104 in the engine compartment, on the RH frame rail under the battery
but i think this is unlikely.
Without a DTC it is hard to help you