I have the same 2007 People S-250. How is the flashing LCD service warning turned off? Didn't quite understand comment above.
Thanks.
The procedure how to reset it is described in the user's manual, take a look.
The service light starts fleshing every 2000 kms.
The service interval for S250 is 3000 kms for version with carb and 6-8.000 kms for version with injection, depending on the market where it's being sold.