Why Does My Check Engine Light Come On?

Don’t make the same mistake many other drivers make and ignore your check engine light. If your vehicle’s onboard computer system issues the warning, there is a good reason why. Thankfully, Advantage Auto Service has the state-of-the-art equipment needed to diagnose and service your engine.

Here are four reasons why you heard the ding and saw the light while driving.

An Oxygen Sensor Issue

Your vehicle’s oxygen sensor is part of the exhaust system and it monitors unburned oxygen in your exhaust. It is mounted to your exhaust manifold and one sure sign of a failing sensor is the CEL warning. Should your vehicle fail a smog test, this, too, could be attributed to a bad oxygen sensor.

The sensor checks how much oxygen is in your fuel mixture. If your vehicle is burning “rich,” it doesn’t have enough oxygen in it. If it’s burning “lean,” the fuel mixture has too much oxygen in it.

Catalytic Converter Failure

Another component of the exhaust system is your catalytic converter and, yes, if it’s failing you will smell rotten eggs. Oftentimes, however, the check engine light will signal a problem long before the rotten-egg smell, and this is why auto technicians recommend bringing a vehicle into the shop the minute the CEL check engine light comes on.

The sooner a catalytic converter problem is isolated the less expensive the repair. Replacing a catalytic converter will set you back $500 to $600 or more.

Mass Airflow Sensor 

The mass airflow sensor has a direct effect on how much fuel your engine uses. A bad mass airflow sensor can cause a reduction in power and fuel economy, as well as damage to your catalytic converter, oxygen sensors, and spark plugs. When the check engine light comes on, swing by the shop and have a mechanic run diagnostics to determine the exact problem and get it corrected.

Spark Plugs or Plug Wires

Your automobile’s check engine light might also come on if your spark plug wires are misfiring or your spark plugs are worn.

You can go much longer between spark plug changes than you use to be able to, but this doesn’t mean the combustion system doesn’t need regular maintenance. The wires create the spark that fires up the plugs and without this combustion, your vehicle won’t start. If you’ve noticed your engine misfiring lately and your check engine light comes on, it could be your plugs or wires.

Loose Gas Cap

Finally, the cause of the check engine light warning could be something as simple as a loose gas cap. Hopefully, you didn’t screw the cap on tightly the last time you fuelled up, but your cap can also lose its seal over time. Check your gas cap to see if that’s the cause of the CEL. If it isn’t, it’s best to have the issue diagnosed properly. As mentioned above, the sooner the problem is found the less expensive the repair, so don’t cause further damage by ignoring your CEL.

Advantage Auto Service offers auto service and repairs in the Marietta, Atlanta, Acworth, Austell, Dallas, Douglasville, Hiram, Kennesaw, Mableton, Powder Springs, Smyrna and Vinings, GA, areas. Call us today at 770-268-2892 if your check engine light has come on.