Sub tank issues

[Not so grey nomad]

Hi Cuppa, that is exactly what I did both times it has tripped, since I have reset the putter I have pumped fuel from sub to main several times with out an issue, however I haven't refilled the tank yet I think you have hit the nail on the head. Have you worked out if topping of the main tanks is the issue or topping of the sub tanks that is the issue, if so let me know if not I will try both separately and see if I can work out which one is the issue.
Thanks again all now I feel I know how to prevent it and also how to reset/fix it if it happens.
Cheers

[the evil twin]

You will find that 99.9% of vehicles will not have an issue with the filling tripping a fault.
The ones that do will be because of an issue with the sender (main or sub as the poota monitors both).

IIRC (and I may easily be wrong) an open main tank sender manifests as off scale high.
A fault like that will trip the Sub Tank transfer system and may occur when filling to the brim if the wiper on the sender is out of adjustment/worn