Just bought a used '01 S60 2.4T yesterday. Car is in fabulous shape for its age. There are a few issues though that I would like to try fixing myself if possible.
One of those is the fuel door latch. I previously had an '02 S60 T5 and the button that unlocked the fuel door latch was located underneath the headlight switch. On this '01, there is no similar button.
I'm thinking the fuel door latch may be controlled by the keyless remote, which seems kind of stupid. If I'm correct, that would mean the fuel door latch is constantly opening and closing every time I use the remote to lock and unlock the car. With my '02, the fuel door latch only unlocked when the button was pushed. Seems like a lot of repetition.
So, that's my first question...on the '01, is it the keyless remote that controls the fuel door latch/locking mechanism?
Second, the fuel door itself is not locking. The latch remains in the open position all the time. I've opened the trunk, then the right side/passenger side cover that exposes the inside of the fuel door. I can see the motor that operates the latch. I can push and pull the latch manually with my fingers to close it, but that's about it.
Any ideas on what I can do to diagnose the problem and fix? Thanks!

 

Fuel filler door
The fuel filler door, located on the right rear fender, is connected to your car's central locking system. The driver's door must be unlocked before the fuel filler door can be opened.

Be sure the fuel filler door is not obstructed and is completely closed after refueling. Open the fuel filler cap slowly during hot weather.
After refueling, close the fuel filler cap by turning it clockwise until it clicks into place.

Test the motor with a voltmeter -- you may also want to check Fuse #15 (Rear Drivers side in trunk)

 

Thank you for the reply and clarification on how the fuel filler door operates. I'll check Fuse #15 and test the motor. Will reply once it's done.

 

Before checking the fuse and motor, I lubed the latch mechanism itself, working the latch back and forth to make sure the lube penetrated thoroughly. That seemed to do the trick. Fuel door latch now locks and unlocks as it should.