Threw a CEL shortly after startup and pulling out of the parking lot after work today. Car is running very smoothly.. no evidence of performance issue. I googled a bit and found a suggestion to clean battery terminals. I checked and one of them did have corrosion on it so I cleaned it up. Any other recommendations? I don't want to take it to the dealer to have gen charge me a $100 diagnostic fee and dismiss it as a random one-off.