scanrps hit it right on the nail. Bring it your Honda dealership. If the emissions light is on for an emissions related problem (which, it usually is) they will repair it free of charge. However, keep in mind that if the repair insn't emissions related, and not covered under the extended warranty... you have to pay for the diagnostics. In my experience with these cars, the problem is usually a bad 02 sensor...which is covered under the warrany. When my light came on, I took my car to Auto Zone to have the codes pulled for free (their diagnostics isn't as accurate or specific... but it will at least give you a general idea) and then I went to the Honda dealership and asked for a copy of everything the warranty coveres. It's a two page list. I found that the 02 sensors were on there, and so I got it repaired at the dealer. The problem with my car was a failed secondary 02 sensor. It had 140,000 miles. I also got the one free tune-up at 90,000 miles.