The check engine light could be on because of just one error code that came in at some moment, and the light won't go away until that error code is cleared.
If you want to be very precise to find out what your problem is, then you can have the car scanned using an OBD II scanner tool... I would have no idea where you could find one. I have a hunch that the suzuki dealership would have one- they'll charge you I can bet, but that's up to you if you want to use this option. I hardly ever give a crap about what the scanner tool says because... for god's sake, I have the internet as a resource, and I've been able to diagnose every problem to ever hit my car with a simple google search.
Plan B (or A for me) is to do it the ghetto way and take off the negative terminal of the battery and leave it off for about a minute or so. Doing so would clear the error code that caused the CEL to be on in the first place (exactly the same way the clock goes back to 1200 after you disconnect the battery) Put it back on and start the car, see if the check engine light is still there. If it is, you know for certain that a sensor needs to be replaced- in all likelihood, it will be the throttle position sensor.
Here are some symptoms to a bad throttle position sensor:
Symptoms of a Bad Throttle Position Sensor