Here's what you should do:
1. Get the diagnostic trouble codes (DTCs): You need to know *why* the check engine light is on. You can do this in a few ways:
* OBD-II scanner: Buy a relatively inexpensive OBD-II code reader from an auto parts store. These plug into your vehicle's OBD-II port (usually under the dashboard) and will display the trouble codes. This is the best option as it gives you specific information.
* Auto parts store: Many auto parts stores will scan your vehicle for free. They can tell you the codes and possibly suggest the problem.
2. Address the problem: Once you have the DTCs, research them online (many resources are available) or consult a repair manual. This will help you identify the likely cause of the check engine light. This could range from a simple sensor issue to something more serious. Do not simply clear the code without fixing the problem; the light will likely return.
3. Repair the problem: Once you've identified the issue, repair it. This might involve replacing a faulty sensor, fixing a leak, or performing more extensive repairs.
4. Clear the code (after repair): *After* you've repaired the problem, you can clear the code. Many OBD-II scanners have a "clear codes" function. Some advanced scanners can even perform more in-depth diagnostics. Your vehicle's computer will typically monitor the system for a period after the code is cleared to ensure the problem is resolved. If the problem persists, the check engine light will return.
Important Considerations:
* Duramax specifics: The Duramax engine is sophisticated. Incorrect repairs can lead to significant damage. If you are not comfortable performing repairs yourself, take your truck to a qualified mechanic specializing in Duramax engines.
* Don't just disconnect the battery: While disconnecting the battery for a period of time might temporarily clear the light, this doesn't solve the underlying problem. The light will reappear.
In short, resetting the check engine light is the *last* step, not the first. Focus on finding and fixing the root cause.
