Why would a 2004 Toyota Solara Engine light come on?

I believe this question has been answered previously (maybe stated a little differently).

The "Check Engine" light means a fault has been detected someplace in the computer controlled systems. The fault can be as simple as a loose gas cap or as complicated as a faulty sensor or even a clogged catalytic converter. The only way to know for sure is to plug an ODB II code reader into the port under the dashboard (to the right of the steering column). The code reader will tell the user exactly what the problem is. Code readers can be borrowed (free) from many auto supply stores.

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