This only happens when I start my bike after I've been riding. Not a cold start
i remembered there was a post about this error code somewhere on the forum...
this happened to me over the weekend. i'd been riding the whole day - pulled over and shut the bike off to take a leak in the woods. turned it back on, hit the starter and it cranked but didn't start or even fire. odd as i've never had a hot start problem before. hit the starter again - same futile cranking. then the dash showed 'sd__19'.
turned key off, back on, and the bike fired right up and ran fine afterwards. went into diagnostics mode and 19 was recorded in the fault code history which i then cleared.
bike has 17.5k miles and the sidestand switch bypassed since day one.
classifying this as a glitch, for now.