1997 Pontiac Bonneville Owner's Manual - Page 261

When you pur the cap back on, turn it to theright (clockwise) until you hear a clicking sound. Make sure you fully &stall the cap. The diagnostic system can determine if the fuel cap has been left off or improperly installed. This would allow fuel to evaporate into the atmosphere. See "Malfunction Indicator Lamp" in the Index. Fuel Door Manual Release (Option) If your vehicle has a fuel door lock, thefuel door can be opened manually in case of an electrical power failure. type. Your dealer can get one for you. I you get f the wrongtype, it may not fit properly. This may cause your malfunction indicator lamp to light and your fuel tank and emissions system may be damaged. See '(Malfunction IndicatorLamp" in the Index. Open the trunk. The release mechanism is on the driver's side of the vehicle, at the top of the trunk compartment. Pull the tab rearward to release the fuel door. Prying ona locked fuel fillerdoor can damage it. Use the remote fuel door manual release located in the trunk.