Engine light

[1fastpug]

What to do with 'check engine light' ?

[-X-]

Check the DIC for Diagnostic Trouble Codes (DTCs):

Hold down the Options button and while doing so press the Fuel button four times, which will automatically display DTCs (then release the Options button). It will keep cycling through each section, write down any codes and report back. Don't clear any codes until you get them written down.

[itsaz]

Originally Posted by -X-

Check the DIC for Diagnostic Trouble Codes (DTCs):

Hold down the Options button and while doing so press the Fuel button four times, which will automatically display DTCs (then release the Options button). It will keep cycling through each section, write down any codes and report back. Don't clear any codes until you get them written down.

Only works on the C5's. For C6's, they want you to call Onstar.

[-X-]

Well, this is the C5 section... The OP never mentioned whether he has a C5 or C6.