Here's the proper procedure:
1. Diagnose the problem: The most reliable way to do this is to use an OBD-II code reader. These are relatively inexpensive and can be purchased at most auto parts stores. The code reader will give you a diagnostic trouble code (DTC) that indicates the specific problem. You can then look up the code online or in a repair manual to understand the issue.
2. Fix the problem: Once you know the DTC, you can address the underlying mechanical or electrical problem. This might involve replacing a sensor, fixing a leak, tightening a connection, or something more complex.
3. Clear the code (after fixing the problem): After you've repaired the issue that triggered the CEL, you can then clear the code. Many OBD-II code readers have a "clear codes" function. Some auto parts stores will also clear the codes for free if you bought the reader from them.
Methods to clear the codes (only after fixing the issue):
* OBD-II Code Reader: The easiest and most reliable way.
* Disconnecting the battery: This is a less reliable method. Disconnect the negative (-) terminal of the battery for at least 30 minutes (some recommend up to an hour). This will often clear the code, but it might not work for all issues and doesn't address the underlying problem. Reconnect the battery and see if the light comes back on.
Important Note: If the check engine light comes back on after clearing the code, the problem hasn't been fully resolved. Return to step 1 and diagnose the issue again. Ignoring the check engine light can lead to further damage to your vehicle.
