The only I would look for is a past history of a leaking battery. Otherwise really great car and even then the leaking battery was just a 3 hour fix.
I would EMPHASIZE checking for signs of a leaking battery - my '98 is in the shop right now with hidden damage issues.
A little background: My baby stalled at a red light last week, didn't die completely but would not accelerate at all. I coasted to the side of the road and called my mechanic, Kevin to report the "Reduced Engine Power" message. After shutting down the engine and talking with Kevin, I cranked her up again and she ran fine. I went to Kevin's shop and he ran diagnostics on it, then recommended I take it to a dealer for replacement of the Tac Module. He could replace the part but did not have the Tech II necessary to reprogram the computer. Imagine my horror when the dealer informed me that there were signs of a past battery leak that has covered/damaged the PCM, Tac module and Wiring Harness with battery acid. He recommended the replacement of said parts to the tune of $3400 parts/labor/tax.
I called Kevin back and he told me to bring the car back to him. As of now he is assessing the damage and trying to come up with an alternate plan. One of my frustrations about the whole thing is I purchased an extended warranty when I bought my car in June, but I've been informed that the damage is not covered by it because it was caused by a non-covered item.
A mechanic that works with Kevin told me that there has been a past issue with AC Delco batteries at the positive post. I can't confirm that but add it here as an FYI.
So I recommend close scrunity of the battery and any signs of past leaks. If you suspect a past leak, be mindful of any crucial electronics nearby. And another thing, why would someone design a car with sensitive electronics located under a battery without allowing for shielding/protection/drainage in case of battery failure??? The serviceman at the dealership said there was a pool of battery acid in the fender well.
Good luck in your search for the right C5. In spite of this setback, I love mine and would still buy it again tomorrow.
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