Here's what you should do:
1. Verify the Repair: Make absolutely sure the new fuel pump is installed correctly and is functioning properly. This includes checking fuel pressure to ensure it's within the manufacturer's specifications. A faulty installation is the most common reason the light remains on.
2. Drive the Car: Drive the car for several ignition cycles, allowing the computer to monitor the fuel system's performance. Sometimes, the light will turn off automatically after the system runs for a while without detecting further problems.
3. Disconnect the Battery: Disconnect the negative terminal of the battery for at least 15-30 minutes. This will reset the computer's memory. Reconnect the battery and try starting the car. This is a simple, but sometimes effective method.
4. OBD-I Scanner (unlikely to be effective): A generic OBD-I scanner *might* be able to clear the code. However, OBD-I systems varied greatly between manufacturers and models, and finding a scanner that works with your specific Buick might be difficult. This is not the most likely solution.
5. Professional Diagnostic: If none of the above works, the best option is to take the car to a mechanic or auto parts store that can diagnose the problem. They have the tools to read the diagnostic trouble code (DTC) stored in the car's computer and determine the root cause of the "Check Engine" light. The light might indicate a problem *other* than the pump, or even a problem *caused* by the pump replacement (a sensor was damaged during the process).
Important Note: Simply ignoring the light is not recommended. The light indicates a problem that could lead to further damage or drivability issues if left unaddressed.
