2017 Prado fuel system malfunction

[Kaitlynnn Lurker Find all posts View Profile Close Kaitlynnn]

Has anyone else had problems with their fuel transfer systems?
started as a flashing fuel light and breaking down at 1/4 tank.
replaced the whole internal sender unit assembly in the main tank, light no longer flashes but now breaking down at 1/2 tank.
have blown out all hoses dropped and drained both tanks, replaced the under body fuel filter.
Does anyone have a detailed diagram of where all the hoses go and connect to?

[RPP Senior Member Find all posts View Profile Close RPP]

go to www.partsouq.com. type in your VIN, then navigate to the drawings for the dual tank configured vehicle.
You will see all the hoses and their circuits.

[carco Advanced Member Find all posts View Profile Close carco]

The 1/4 tank issue sounds like the in tank transfer pump playing up.
Did you test it?

[Kaitlynnn Lurker Find all posts View Profile Close Kaitlynnn]

Have replaced the whole sender unit assembly in the main tank

[RPP Senior Member Find all posts View Profile Close RPP]

Another option:
There is a well hidden fuel tank breather valve under the chassis and above the rear diff.
It sits off a 'T' junction connected to hoses from both tanks.
If it is clogged it could impede the fuel transfer process as the rear tank needs to inhale air to replace the fuel.
The valve is bi-directional, however the opening in the inhaling direction is tiny (needle thin) and easily clogged by fine dust.