Our 05 Corolla with 79000km on it has had the check engine light go on occasionally lately. Took it to the dealer tonight to have it diagnosed and they said it needs a charcoal filter. Something to do with the emission system. The dealer wanted $638. (no warranty) including installation for it. Since the check engine light hasn't been on for a few days, and I didn't have close to $700. burning a hole in my pocket, I paid for the diagnosis ($109.) and left. Anyone have any experience with this? What could go wrong with a charcoal filter in only 79,000km?