a bit of info i found out today,
i have a 07 cmax, and the other day the dash light flashed up "engine systems fault" so instead of going to ford, i bought of ebay a fault reader.
i plugged it in and no fault was found, but it did reset it and clear the dash info,
only when i drove it again the fault came back, after many hours of messing i discovered the fault came on when i braked,
it turned out the brake light fuse had gone, replaced the fuse, cleared the code, and everything is fine now,,,,
"Ford" wanted £75 just to plug it in to their fault reader, the fuse was 50p