Q: My car was working perfectly the today I was stopped at a light when it turned gree I pressed the gas and it did not. I turned off

The clues to what that was all about are within the trouble code(s) that were stored when the check engine light illuminated. Those codes, which can be downloaded, are not themselves a diagnostic or pinpoint identification of the failed or failing component, but they will provide guidance to a mechanic as to what "systems" should be directly tested. To have this investigated to see if there is an incipient part/component failure that can be resolved now, before you perhaps later get stranded, you can request a check engine light diagnostic. During such a diagnostic, a certified mechanic from YourMechanic would retrieve all the diagnostic trouble code(s) from your car’s PCM that caused the check engine light to illuminate (even if the light is now off). Using those trouble codes, the appropriate individual vehicle components or sub-systems (often a sensor, circuit, and the like) are tested to pinpoint the cause of the fault or the reason why the check engine light has illuminated. If and once, a faulty part or component is identified, it is explained to your satisfaction and the mechanic will let you know of the cost to repair. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.