Td42 fuel tank fault

[Cam swag]

Hey guys having trouble with my 2002 td42
Both fuel gauges are on empty and sub light is on have tried resetting by disconnecting battery and the sub light goes away for a couple seconds and turns back on has anyone got some ideas on what it could be sorry if this has been asked before any help will be greatly appreciated

[MB]

G’day Cam, I’m an electrical in-depth nuffy but most TD42 and other variant GU’s owned always seem to be Earth issues in the end somewhere throughout our trucks. Others will hopefully point you in the knowledgeable direction mate!
Was told on the weekend just gone that major stock working gauge discrepancies between two identical GU’s was also Earth issues again :-(


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[the evil twin]

What MB said X2

While ever there is a fault (or it thinks there is a fault) in the gauge senders the sub-tank light will illuminate and you also won't be able to transfer.

There is a method to get the fault code/s from the sub-tank computer but it can be a PIA and in your case may not help all that much.

On all my GU's I have added an extra earth from rear chassis to body and from front chassis to engine.
About the only earth issue you will get after that is in the Instrument Cluster itself, rare but happens.

Now, it may not be an earthing issue but it is def worth doing.
I also assume all was OK and then both gauges and the sub-tank warning happened at the same time and you have checked the fuses?

[Cam swag]

Yer have done thanks heaps will give it a go