Water in Fuel

If you have water leaking in, which I doubt, you would have fuel leaking out. Do you see fuel leaking out?

 

Just random thoughts. I don't have the same truck as you.
Put the old fuel caps back on. See if the warning reverts to the way it was.
Does your caps have seals? Change the seals.

Where is the fuel/water sensor? In the fuel tank or by the filter?

Could it be a short in the wire harness that gets wet when it rains?

 

You might try this stuff:



I drive a ‘20 T680. I had a dozen random codes stored and one was for water in the fuel. Tech said to not worry about it.

 

Can you drain the fuel filter? Is there a water sensor at the bottom of the fuel filter?

I also use Fuel Doctor every fill, not only disperses water but cleans the fuel system and controls algal issues. I find FD with standard diesel is the same price as premium diesel but achieves more.

 

If the WIF light is on, crack the drain on the seperator open slightly. Drain some fuel into a clear container and see if there is actually water in there.

If there is water, find out how its getting into the tank.

If its just diesel, troubleshoot the WIF wiring/sensor. It could be getting triggered by water spray from the road getting into a plug or damaged spot in the wiring.

 

I get the same notification in heavy rain in my 2018 international, it goes away after a few minutes. I just ignore it, my fuel water separator filter doesn’t show any increase.