* Check Engine Light (CEL) Codes (Diagnostic Trouble Codes - DTCs): These are stored by the Powertrain Control Module (PCM). The simplest method to clear these is to disconnect the negative (-) battery cable for at least 30 minutes. This will drain the power from the PCM and clear the codes. However, this will *not* fix the underlying problem that caused the codes. After reconnecting the battery, the PCM will re-run self-diagnostics. If the problem persists, the CEL will likely return.
* Other System Codes (ABS, Airbag, etc.): These systems might have their own individual modules that store codes, and clearing them might require more specialized tools. Disconnecting the battery might work for some, but not all. You might need a scan tool that can communicate with those specific modules to clear their codes.
Important Considerations:
* OBD-II Scan Tool: The best way to diagnose and clear codes is with an OBD-II scan tool. These are relatively inexpensive and widely available at auto parts stores. They will tell you exactly *what* codes are stored, which is crucial for fixing the issue. Simply clearing codes without understanding the problem is not recommended.
* Professional Diagnosis: If you're not comfortable working with your car's electrical system, or if the CEL returns after clearing the codes, take your Buick to a qualified mechanic for diagnosis and repair. Ignoring check engine lights can lead to further, more expensive damage.
* Battery Safety: When disconnecting the battery, always disconnect the negative terminal first and reconnect it last. This prevents accidental shorts.
In short: The battery disconnect method is a quick, simple way to *clear* codes, but not a solution to underlying problems. An OBD-II scan tool is highly recommended for proper diagnosis and code clearing.
