It's very surprising that's all you lost. GM cleverly designed the car so you can't replace a broken radio. You must get it repaired through the dealer and one of their two grossly over-priced repair centers. To address that lack of concern for their customers, some aftermarket stereo companies came up with "radio relocation kits" that allow you to mount the original radio in the trunk and put a new one in the dash.
It is likely the installer had to disconnect the battery and that is under the hood. The Engine Computer needs time to relearn the sensor readings and engine operating conditions. That relearn starts to take place as soon as you start driving the car but it typically only takes a few miles before normal performance is restored. If the installer disconnected or changed something that affects performance enough to be noticed and forgot to put it back, the Engine Computer will detect it, set a related diagnostic fault code, and turn on the Check Engine light if the problem could affect emissions.
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Thursday, February 28th, 2013 AT 10:36 PM