Just kidding, but that message did start appearing this evening (at 9300 miles). The 2015 FFH manual says to use Motorcraft Premium Windshield Washer Concentrate With Bitterant, Ford part number / Ford specification ZC-32-B2 (U.S.) / WSB-M8B16-A2. The parts department of my Ford dealer is closed until Monday so I searched a bit on the internet. I found ZC-32-B (no "2") concentrate, 32 ounce size, about $11. I also found on various "Ford parts" sites ZC-32-B2 (with the "2") for $2-$3 with no description of size etc. The cost of either is so low it's not a factor; I'm just curious what the low-priced ZC-32-B2 actually is. Is a one-shot size? Is it a concentrate or already mixed? Etc...