From the rear seat...but I wouldn't jump to conclusions yet. This is a list for that code;
P0440 (evap emission control sys malfunction). Troubled areas:
Hose cracked, holed, damage or loose seal.
Fuel tank cap not installed properly, cracked or damage.
Vac hose cracked, holed, blocked, damage or disconnected.
Fuel tank cracked, holed or damage.
Charcoal canister cracked, holed or damage.
Open or short in vapor pressure sensor circuit.
Vapor pressure sensor.
Fuel tank over fill check valve cranked or damage.
I know our cars don't like to be completely filled with gas, especially past the point to where the gas pump automatically stops. The purge EVAP valve can get stuck. Honestly what I would do since you didn't pull any of the other codes, is to make sure the gas cap seal is good and that it is on there good and tight(few clicks). The IS300 picks up on a loose/bad cap very good. Then I would drive it a bit to use maybe an 1/8 of a tank. Then the code will either go away on its own or you can pull the negative off your battery for a few minutes to reset the code. If the code comes back then you may have to look at getting to the charcoal canister to check the vent. I don't know if you did/do, but I would always stop refueling when it stops itself. I would wait and see what happens.
'02 IS300 MSM LSD