There are two main ways people try to reset the CEL, neither of which is a proper solution unless the problem is already fixed:
* Disconnecting the battery: This is the most common method. Disconnect the negative (-) battery terminal for at least 10-15 minutes. This clears the computer's memory, including the trouble code that triggered the CEL. However, the light will likely return if the issue persists. This is only a temporary solution.
* OBD-II Scanner: A scan tool can read the diagnostic trouble codes (DTCs) stored in the car's computer. These codes indicate the specific problem(s) causing the CEL. Many inexpensive OBD-II scanners are available. *After* fixing the problem indicated by the code, you can use the scanner to clear the codes, which will also turn off the CEL. This is the best method.
Therefore, the correct procedure is:
1. Diagnose the problem: Use an OBD-II scanner to determine the trouble codes. This will tell you what's wrong.
2. Repair the problem: Fix the issue causing the CEL. This might be something simple (loose gas cap) or more complex (sensor failure).
3. Clear the codes: After the repair, use the OBD-II scanner to clear the codes (or disconnect the battery as a less precise alternative).
Ignoring the check engine light is dangerous. The underlying issue could cause further damage to your engine or affect your car's emissions and safety. Ignoring it for too long could lead to more costly repairs down the line.
In short, don't just reset the light – find out why it's on and fix the problem.
