The check engine light just came on in my 2000 Camry. It has 180,781 miles, and the 180k mark is the recommended timing belt replacement mark. I've checked the tightness on the gas cap, and I'm hoping that the light is on just to get me to take my car in to have the timing belt changed. Does Toyota do this? It seems like a good move on their part. Anyway, I've already had the timing belt changed, and I'm just hoping my mechanic didn't reset whatever needs to be reset to prevent the light from showing up.
There's no immediate way to just know what's wrong, what you need to do is take the car to an advance auto or autozone and have them hook up and ODB-II code reader. They will tell you what code is coming up and can clear the code for you if you'd like. This is a free service, and they will often be able to recommend parts or service based on the CEL reading.
at 180,000 unless you're experiencing some change in the way the vehicle drives it could easily be an O2 sensor if they haven't been changed out during the course of your ownership, but that's 100% a shot in the dark. It could also be a 1 or very few time misfire that occurred, and that would clear itself after 50 miles driving.
I don't think it's got anything to do with the timing belt change interval, but the only way to find out is to hook up the car to an appropriate code reader to find out what code is triggering the check engine light.
It could be anything. The best diagnostic tool you can use when a light comes on is an OBD (II) scan tool.
It's a waste of time to look the car over at this point. You'll spend hours chasing ghosts without the scanner.
Changed the EGR valve and the light still came back on after 18 miles. Did some research and changed modulator valve for a mere $20.00 more and the check engine light has disappeared. My recommendation is to change both to solve your check engine light problem. this light had been on for two years and i finally solved the problem for $75.00 total and was able to do the work myself. The code for the above is 401 egr valve, etc. Good luck