Wondering what causes the Check Engine Light to Come On?

You may be driving smoothly along when all of a sudden you see the “Check Engine” light illuminate on your dashboard.  You start to worry about what causes the check engine light to come on.  This little light could be the first warning sign of an engine problem.  Unless your car doesn’t run at all, head to your auto repair shop as soon as you can for a diagnostic test.  Your mechanic will hook up a specialized computer to your vehicle to “read” what is going on under the hood.  Potential problems can be diagnosed and fixed while they are small problems, and before they turn into major engine repair.  

There are few problems that can cause the check engine light to come on:

1. Faulty Gas Cap – When the gas cap is loose or cracked, fuel vapors leak out and can throw the whole fuel system off.
2. Faulty Oxygen Sensor – If the oxygen sensor fails, it’s not providing the right data to the car’s computer to monitor the unburned oxygen from the exhaust and how much fuel should be burned. 
3. Failing Catalytic Convertor – If the catalytic convertor fails, it can’t do its job of reducing exhaust gases. It converts carbon monoxide and other harmful materials into harmless emissions.
4. Faulty Mass Airflow Sensor – The mass airflow sensor tells the car's computer to add the proper amount of fuel based on the air coming through to the engine.  Most mass airflow sensors fail because of an improperly installed or it becomes clogged.
5. Bad 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.  You will start to notice misfiring when spark plugs go bad.

Any of the issues listed above can result in reduced fuel efficiency, an increase in toxic fumes from your exhaust, loss of power, rough idling, or not running at all.   If you want to prevent major and expensive engine repair, as well as keep your vehicle a reliable means of transportation, don’t neglect regular engine service.  

If you need to know more about what causes the check engine light to come on, call our ASE Certified technicians at Auto & Fleet Mechanic for more information about engine repair and to make an appointment. Our auto repair shop proudly serves residents in Modesto, CA, and the surrounding area.