How to Check the Gas Cap on a 2004 Pontiac Grand Prix

The 2004 Pontiac Grand Prix cars were built in Canada.

The 2004 Pontiac Grand Prix was equipped with a 3.8-liter 200-horsepower V-6 engine in the base model. A 3.8-liter SFI supercharged V-6 was available in upgraded models. The fuel cap light illuminates when the vehicle's onboard computer recognizes a vapor leak or loss of pressure in the filler neck. This light is controlled by the same OBD-II computer system as the rest of the car. A loose fuel cap can also cause the "Check Engine" light to illuminate.

Things You'll Need

• OBD-II scanner

Instructions

1. Open the fuel filler door. Tighten the fuel cap. Shut the fuel filler door.

2. Open the driver's door and kneel next to the driver's seat. Locate the OBD-II plug port underneath the dashboard. Plug the OBD-II scanner into the plug port beneath the dash. Sit in the driver's seat of the Grand Prix.

3. Turn the ignition key to the "II" accessories position. Turn the scanner on if needed. Select the year, make and model on the scanner's main menu. Use the "Up" or "Down" arrows to select your answers. Press the "Read" button to submit your answers. Select the option to read trouble codes. Allow the scanner to communicate with the vehicle.

4. Press the "Erase" button when the code for the fuel cap is presented on the scanner. Remove the fuel cap trouble code from the car's computer. Remove the scanner from the Grand Prix.

5. Drive the car as you normally would. If the "Check Engine" light illuminates, retest the computer with your scanner. If the fuel cap code has appeared again, replace your fuel cap.

References

• MSN Autos: 2004 Pontiac Grand Prix Specifications and Reviews