150 fuel transfer problems...

[davo53 Lurker Find all posts View Profile Close davo53]

Hi all . Coming back from a trip after escaping covid ridden Melbourne , nearly home on the freeway in the rain , low fuel light starts flashing . Fuel gauge showed 1/4 full and range showed about 350k . Put some fuel in at the first servo , and light went out , but not good for peace of mind . Assuming fuel is not transferring from rear to main tank . Changed the inter tank filter which looked fine . Did some reading and
some thinking .
At the fuel pump relay on the fuse box , there is 12V on on side of the relay contacts . No resistance to ground on the other side . Is there a direct connection between the relay and the pump ? If so this would suggest a wiring or pump fault .
Does anyone have access to a cct diagram of this part of the wiring so I can confirm this ?

Cheers Dave

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

Tried to PM you but this forum software is the pits..
Anyway here's your wiring diagram, fuel pump is on the very left side of the pdf https://www.dropbox.com/s/jfwj7bo0t0...S-1KD.pdf?dl=0

[davo53 Lurker Find all posts View Profile Close davo53]

Thanks Adrian . It formats really weirdly on my laptop ,and I cant read the text , but if i am reading it correctly , power goes through a fuse to a relay controlled by the ECM , and relay goes directly to fuel pump . So open circuit on output of relay means either wiring fault or more likely dead pump.
Much appreciated . Does anyone know if its possible to remove and replace the electrical connector to the main tank with the tank in situ ? That would enable a final check before removing the tank .

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

Thanks Adrian . It formats really weirdly on my laptop ,and I cant read the text , but if i am reading it correctly , power goes through a fuse to a relay controlled by the ECM , and relay goes directly to fuel pump . So open circuit on output of relay means either wiring fault or more likely dead pump.
Much appreciated . Does anyone know if its possible to remove and replace the electrical connector to the main tank with the tank in situ ? That would enable a final check before removing the tank .

If you zoom in on the pdf and scroll left it should show ok, works fine on acrobat reader on my win 10 laptop?

Fold the 2nd row left seat forward and fold the carpet back there is an access hatch in the floor above the tank where you can access the plug. You'll need to drop the tank to remove the pump module though.

[davo53 Lurker Find all posts View Profile Close davo53]

Thanks . Let the adventure begin !

[antd Lurker Find all posts View Profile Close antd]

What was the outcome? Same issue here…

[humungusmon Junior Member Find all posts View Profile Close humungusmon]

Hi, I had a similar issue in the middle of the Gibson desert.

In my case the front tank was dry but the rear tank was full, which is backwards to how it's supposed to work. I would confirm that yours is the same before doing what I had to do.

It turns out that there is a fuel pump and mesh filter attached to the float oin the rear tank, and in my case the pump or mesh had become clogged. The pump is a service item at 150 000kms. It's called "Replace fuel transfer pump (diesel models)".

You may need to have the pump or whole lot replaced. Good luck.

[humungusmon Junior Member Find all posts View Profile Close humungusmon]

[davo53 Lurker Find all posts View Profile Close davo53]

Well , I got access to the connector but no way could I get it off . Scared of breaking something . I' m in Frankston Victoria . Anyone like to recommend someone to replace the pump for me ?

[davo53 Lurker Find all posts View Profile Close davo53]

Well I've had another look into the problem . Really want to confirm there is power getting to the pump . Pulled the carpet out further to get better access to the inspection cover in the floor . Still can't get the connector off the tank . Has anyone does this , and knows the secret? After jiggling things around I can now measure about 3000 ohms to ground at the output of the pump relay , whereas before I was getting an open circuit . This seems too high to be the pump . Anyone got any thoughts ? Would be really nice if it was just a bad connection , but without getting the plug off its hard to know .

BTW there is an excellent video on Youtube showing how the Prado fuel transfer works . Search Toyota Prado sub tank jet pump .

[davo53 Lurker Find all posts View Profile Close davo53]

Success at last ! I was doing the right things , the plug was just incredibly tight . Had to hold a flathead nail in a pair of vice grips to pull up on the edge of the plug . That was a struggle! If only Mr T had made the hole in the floor a bit bigger ....
The result ? Continuity from the plug to the relay , and from the plug to ground . Open circuit on the pump connector on the tank . Now I know its internal to the tank , out it comes .

Just as an aside , for giggles I asked my dealer for a price to replace the pump . They sent me a quote which seemed very reasonable until I checked the part numbers , they had quoted for a tank module without a transfer pump in it . I pointed this out to them and asked for a quote with the correct parts , they never got back to me . Doesn't fill you full of confidence .