Hi, I can help with this. There are a few systems that can cause this with a low fuel tank.
Number one is the evaporative emissions system. This is for detecting any fuel vapor leaks in the fuel tank or vapor recovery system of the car.
The best way to go about this is to have a large national chain parts store pull the trouble code for you. This is usually free of charge. Then I can pin point the issue.
Ok, the p0401 is for the egr system Usually it is a blocked passage in the intake manifolfd. This requires the throttle body to be removed and then clean out the egr port from behind it.
The other code relates to the fuel gauge sending unit. Is the gauge working ok?
The dealer will have experience with this.
The fuel gauge issue will require a special tool to repair it if the gauge isnt working right.