Preventative maintenance should be referenced in your owner's manual, and, while repairing or having your 'Service Engine Soon' light repaired, if your vehicle is due for maintenance, yes. As described in your owner's manual, this maintenance will help prevent future issues.

Possibly. Sometimes, the triggering device will reset itself thus turning off the 'Service Engine Soon' light until that device/sensor is tested by the vehicles on board computer again. If it fails the test again when tested, the 'Service Engine Soon' light will illuminate once again. Some devices/sensors when tested and failed will illuminate the 'Service Engine Soon' and it will not go out until correct service work is performed.

General Motors has designed the vehicle to inform its driver if there is an issue with certain devices/sensors that effect the drivability/emissions. If this is ignored, there is a possibility that the drivability will suffer, fuel economy will be decreased, or the emissions being emitted will be increased. Do not ignore the 'Service Engine Soon' light.

No. When state and local officials perform certified emission tests, one of the first steps in the process is to inspect for a 'Service Engine Soon'. If it is on, it will automatically fail the test.