Yup, wrong forum - this is for P3 cars.
However as said above, you've got a couple of unrelated faults, the DIM on 2000-2004 cars has a well known fault that causes multiple issues as they age. Easy quick fix, look up Spokulozik in the P2 traders section.
Sounds like a failing relay in the REM, the rear doors are controlled from that module as far as I know.
And either a blocked fuel filter or in-tank pump causing the car to run out of fuel early, it actually can't access the last 1/8th tank if the pump or transfer piping in the tank has failed.
Anyway, the correct place to ask questions about your car is here
https://www.volvoforums.org.uk/forumdisplay.php?f=19