How do you reset the service engine soon light on a 1999 Pontiac grand prix gt?

The 1999 Pontiac Grand Prix GT, like many cars from that era, doesn't have a simple button to reset the "Service Engine Soon" light (SES light or Check Engine light). The light comes on because the car's onboard diagnostic system (OBD II) has detected a problem. Simply resetting the light without addressing the underlying issue will likely cause it to come back on.

Here's what you should do:

1. Diagnose the problem: You need to find out *why* the light is on. The easiest way is to use an OBD II code reader. These are inexpensive and readily available at auto parts stores. The code reader will give you a diagnostic trouble code (DTC), which you can then look up online to understand the problem.

2. Fix the problem: Once you know the code, research the potential causes and fix the underlying issue. This might involve replacing a sensor, fixing a leak, or other repairs.

3. Clear the code (after fixing the problem): Once the problem is resolved, you can clear the code. Many code readers have a "clear codes" function. Alternatively, some auto parts stores will clear the code for free if you bought a part from them.

Important Considerations:

* Don't just disconnect the battery: While disconnecting the battery for a while might temporarily clear the light, it won't solve the problem. The light will return once the car's computer detects the issue again.

* Professional help: If you're not comfortable diagnosing and repairing the issue yourself, take your car to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and make the necessary repairs.

In short: Focus on *fixing the problem*, not just resetting the light. The light is a warning sign, and ignoring it could lead to more significant damage to your car.