After I had just finished installing new Timing Belt and then the " Service
> Engine Soon " light came on. Is this a Preset lite for Periodic Maintenance
> or is it a trouble Code?
Trouble code.
Can I turn it off?
Not adviseable until you determine the cause.
I have an OBD II scanner which I have never used before, but I still wonder
> if that particular Service Engine lite is separate from the diagnostics?
Nope, not separate. The OBD2 protocols eliminate the need for periodic maintenance warning lights for the emissions system.
Any advice-thank you.
Plug in your scanner and see what the problem is.