What Can Cause a “Service Engine Soon” Light to Come On?

Regular engine service is the best way to make sure your vehicle provides you with reliable transportation as long as you want it to.  If you think you are starting to experience engine issues, the “Service Engine Soon” light illuminating on the instrument panel could be the first warning sign.  Unless your car doesn’t run at all, head to your auto repair shop and ask for a diagnostic test.  Your auto mechanic will plug a small computer underneath the dashboard to “read” what is happening under the hood.  Potential issues can be diagnosed while they are small problems before they turn into a major engine repair.  

If you’re wondering what can cause a “service engine soon” light to come on, there are few reasons. It could be an easy fix or something more serious is happening under the hood.

1. A Loose or Faulty Gas Cap – If the gas cap is loose, fuel vapors leak out and can throw the complete fuel system off, reducing gas mileage and increasing toxic emissions.  Replacing the gas cap may take care of the issue.
2. Faulty Oxygen Sensor – The oxygen sensor monitors the unburned oxygen from the exhaust, and how much fuel is burned.  If the sensor is faulty, it cannot provide the right data to the computer, thereby reducing gas mileage and increasing toxic emissions. 
3. Failing Catalytic Convertor – The catalytic convertor reduces exhaust gases by converting carbon monoxide and other harmful materials into harmless emissions. If it fails, your gas mileage decreases, and your car won’t accelerate when you step on the gas pedal. 
4. Mass Airflow Sensor is Faulty – The mass airflow sensor tells the car's computer to add the proper amount of fuel based on the air going through to the engine.  If it fails, toxic emissions will increase, the vehicle may also start to stall, and gas mileage will poor. 
5. Dirty Spark Plugs and Wires – The spark plug seals the combustion chamber and provides a gap for a spark to jump across and initiates combustion in your engine.  If they are going bad, they will misfire.  They simply want to be replaced.

Now, do you understand what is “key” to a well-running engine?  To put it simply—take care of all service items as recommended by the manufacturer, thus helping prevent a major and costly engine repair.  

If you want to know more about what can cause a “service engine soon” light to come on, consult our ASE Certified Technicians at Rum River Automotive about a needed engine repair and to make an appointment.  Since 1997, our auto repair shop has served vehicle owners in Princeton, MN, and in the surrounding areas of Milaca, MN, and Zimmerman, MN.