Here's the proper procedure:
1. Identify the problem: You *must* first determine what triggered the SES light. This usually requires using an OBD-II code reader. These are inexpensive and available at most auto parts stores. The code reader will give you a diagnostic trouble code (DTC) which you can then look up online (many free resources are available) to understand the potential problem. Common causes include things like:
* Oxygen sensor malfunction: A frequent culprit.
* Mass airflow sensor (MAF) issue: Affects the air/fuel mixture.
* Catalytic converter problems: Can be expensive to repair.
* Spark plug or ignition coil failure: Misfires are often the cause.
* Loose gas cap: This is the simplest possible cause. Check this first!
2. Fix the problem: Once you know the DTC, address the underlying mechanical or electrical problem. This may involve replacing a faulty sensor, fixing a wiring issue, or performing more extensive repairs.
3. Clear the code (after repair): *Only after* repairing the identified problem, you can clear the code. There are a few ways to do this:
* OBD-II code reader: Most code readers have a "clear codes" function. This is the easiest and recommended method.
* Disconnect the battery: Disconnect the negative (-) battery terminal for about 10-15 minutes. This often clears the code, but it's not guaranteed to work for all problems, especially if the problem is serious. This also resets other settings in your car.
Important Note: Simply clearing the code without fixing the problem is not a solution. It will likely return very soon, and the underlying issue may worsen, potentially causing more damage to your engine. It's crucial to diagnose and fix the problem properly.
If you're not comfortable performing these steps yourself, take your 1997 Nissan Sentra GXE to a qualified mechanic for diagnosis and repair. Attempting to fix a complex engine problem without proper knowledge could lead to further complications and more expensive repairs.
