Im not sure if your model has it but it could be a problem with your SLS i woudl definatly recomend going over the the 190 revolution page and checking out the forums there, there is a virtual plethora of information spewing from members (many are also members on this forum, as well as bnzsport.com, and benzworld.org) the best thing to do would be to try and find someone who had the same problem you have, that way much less troubleshooting goes into solving the situation.
Good Luck!