I've already been thru this. The pressure sensor has three wires on it, one is 5 volts in, one is ground and one is the output signal. Mine lost it's ground, causing the output to go to 5 volts, indicating high pressure in the tank and setting the light.

With the top up, unlatch the top from the windsheild frame.
Hit the button, the window will go up, the lid will open. Release the button when the lid is all the way open.

Looking into the top storage area, you will see the fuel pressure sensor and fuel gauge connectors together in the top of the tank, center of the car. I had washed the car with the top down and let a LITTLE water trickle into the connectors, corroding them.

I disconnected the connector (the two wire is the fuel gauge, the three wire is the pressure sensor) and cleaned the connectors and pins with alcohol. The light went out in about a day after that!

I used a digital meter on the sensor output and measured the voltage, it was around 2.5 most of the time, but as I wiggled the connector, I saw it spike to 5 volts - cleaning the contacts cured this. Again, it took about a day (actually about 4 or 5 engine starts/short drives and shutdowns) to get the light to reset.