Q&A

 Master

If you have the "Service Engine Soon"light on (poor terminology by Nissan implies your car may need an oil change) your car's computer has sensed a problem with the emission control system in your car that may or may not cause a noticeable drivability problem with your car.
The problem may be very minor or serious but requires a scan tool that plugs into a 16 pin diagnostic socket under the driver's side of your dash board. The scan tool communicates with your car's computer and holds valuable information regarding the fault in your car.
Any reputable automotive repair shop should have the tool necessary to diagnose the fault.