So...about a month ago I hopped into the Vette to go grab some coffee...turn the key and nothing. No crank. No start. All the lights came on and gauges did their sweep as normal. I tried a bunch of times and nothing. So, I unhooked the negative battery cable and re-installed. Car started fine. Two weeks later, same thing...only this time I was in a parking lot grabbing some lunch. I had no tools. I eventually got it to start. Got home and pulled codes (I turned the car off before I thought of pulling codes, so they were all history codes...P1431, P1631, B2721, U1016.

The B2721 caught my attention as it is a Passkey trouble code. So, I used isopropyl alcohol and cleaned the pellet in the key. I also put some extra alcohol on the key, especially around the pellet and inserted and removed key a couple dozen times, hoping to clean the contacts within the lock cylinder itself. At this time, it also occurred to me that my battery may be getting old. I checked my records and yep, over 8 years old. Now, I have never had an issue with the battery up to this point and it would still crank the engine no problem. But, knowing that our C5's are so sensitive to voltage, I decided time to replace, so I bought a DieHard Platinum AGM Battery, Group Size 78, 740 CCA from Advanced Auto Parts.

So far, two weeks later, no issues. So, I cannot say for sure if it was the cleaning of the resistance pellet and contacts or the battery that solved the issue. But, wanted to pass along my experience...

 

Thanks for the info! I would bet most of the issue was the battery. However, it doesn't hurt to have cleaned things out.