* Get the Diagnostic Trouble Code (DTC): The most important step is to get the DTC. This is a code stored by the car's computer that gives a clue to the problem. You can do this in a few ways:
* OBD-II Scanner: The cheapest and easiest way is to buy a relatively inexpensive OBD-II scanner at an auto parts store. Plug it into the car's OBD-II port (usually under the dashboard), and it will read the code(s).
* Auto Parts Store: Most auto parts stores will scan your car for free. They'll give you the code(s) and may even offer a suggestion, but keep in mind they are trying to sell you parts.
* Mechanic: A mechanic will have the tools to read the codes and can properly diagnose and repair the issue.
* Once you have the code(s): Search online for the code(s) (e.g., "P0171 Chevy Cavalier"). This will give you a better idea of the potential problem. Common issues in Cavaliers of that year include:
* Oxygen sensor problems: These are relatively common and relatively inexpensive to replace.
* Mass airflow sensor (MAF) issues: The MAF sensor measures the amount of air entering the engine; a faulty sensor can cause poor performance and a check engine light.
* Catalytic converter problems: These are more expensive to replace.
* Ignition system problems: Issues with spark plugs, wires, or the ignition coil can trigger the light.
* Other sensor problems: Various other sensors (temperature, crankshaft position, etc.) can cause problems.
* Don't ignore the light: Driving with a check engine light on can potentially cause further damage to your engine.
In short, getting the DTC is crucial. Then you can research the code or consult a mechanic for a proper diagnosis and repair.
