I found that process on here a few months ago...i think it's in the changing filter thread...I had the flashing light last year sometime, drained the filter housing and it cleared...just after this my mates hilux had the solid light which didnt clear after draining...he took it to toyota and they charged him $80 to clear it :O
Then a few months ago i had the solid light (which didn't clear after cleaning/filter change) and i spoke to my mate who told me about toyota charging him $80...I was like 'screw that' NewHilux will have an answer...and sure enough it did
Whenever I get a fuel light (twice so far) water or clogged...it gets a new filter...
I'm pretty sure toyota has made the clogged filter (solid light) un-clearable (unless you know that disconnecting trick) so you have to take it to toyota for a filter change and reset...so they get a bit more money out of you!
p.s. it'a good to have this as a seperate thread...as it took me a bit of searching to find it before...