Here's the proper procedure:
1. Diagnose the problem: The best way to do this is to use an OBDII code reader. These are inexpensive and readily available at auto parts stores. Plug it into the OBDII port (usually under the dashboard) and it will display diagnostic trouble codes (DTCs). These codes will tell you what the problem is.
2. Fix the problem: Once you know the code(s), you can research the problem online or consult a repair manual. Sometimes it's a simple fix (like a loose gas cap), other times it requires more involved repairs. Fix the issue causing the light to illuminate.
3. Clear the code (after repair): *After* you've fixed the problem that triggered the SES light, you can clear the code. Many OBDII code readers have a "clear codes" function. Some high-end readers even allow you to erase specific codes, which is useful if you fixed one of multiple problems.
4. Drive the vehicle: Drive the vehicle for a few drive cycles (this usually means several starts and stops, and some time at highway speeds). The computer monitors the system for a while to ensure the problem is resolved before turning off the SES light permanently.
Methods that *don't* work (and shouldn't be attempted):
* Disconnecting the battery: While disconnecting the battery *might* temporarily clear the light, it doesn't actually fix the underlying problem. The light will likely come back on.
* Pulling fuses: This is similar to disconnecting the battery; it's a temporary fix that doesn't address the root cause.
In short, address the problem, not the symptom. Use an OBDII scanner to find the problem and fix it. Only then should you clear the code. If you're not comfortable diagnosing and repairing the issue yourself, take your Tahoe to a qualified mechanic.
