If there is rain, snow, fog, moisture or salt from the roads builds up or collects on the emblem of my pilot, I get a warning saying something to the effect of Some Driver Assist Systems cannot operate clean area shown. This is quite dangerous when you live in the Midwest snowbelt. You cant always pull over and clean it. The system will repeat the message even after acknowledging the issue, if it clears itself or improves, which is equally alarming.