I have exactly the same problem on my 04 ST. Looking for answers too! Other threads seem to indicate the (right hand) knock sensor or the vacuum system under the air box where there is a 5-way tee connecting all the vacuum pipes; the fault can be addressed by cleaning the Tee and replacing the pipe. I'm going to do a bit more research but I'll let you know if I succeed in fixing the issue.thank you Chuck Fl comes on at 80mph or about does not seem to have any affect on bike yet once I stop and kill red switch it off until next time seems to b when you get up in speed it comes on anyone have similar issues
Ginge 431