I'v just got my D40 back after being without it for 19 days reagrding 4wd lights. This is the second time it had been in for the same problem last time I was without the car for over 20 days.
My diagram had all 4 wheels illuminated and 4 lo written under it even when it was in 2wd.
All three sensors have been changed on the transfer case twice.
First started seeing this around 80,000km it now has 105,000 all highway use