Engine Diagnostics

What does the check engine light usually mean?

It’s a scenario that’s befallen drivers everywhere:

They turn on the car and start to fiddle with the radio and the air. They glance left and right over their shoulders while buckling up to check whether they’re clear to back up. They put the car in gear, ease it down the driveway and go on their way. Then suddenly they glance down at the dash and notice with horror, the check engine light is on!

What does this mean? Well, for starters probably a pretty annoying day. If your check engine light is illuminated, it’s best to take it in for diagnostic testing with one of our service technicians. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There’s a problem with the car’s emissions system. The on-board diagnostics system and engine control unit are in charge of monitoring a bunch of different parameters, and if they get a reading that’s a little out of whack, up pops the check engine light.

The list of things that can trigger the check engine light is pretty lengthy. For example, anything from a loose gas cap to a faulty fuel injector can be to blame. Some other potential culprits that can cause that malevolent glow include:

  • A faulty sensor or evaporative system leak
  • Faulty oxygen sensors
  • Worn-out spark plugs or direct ignition coils
  • Loose or cracked hoses and manifolds
  • Sticky exhaust gas recirculation valves
  • Pinched or deteriorated fuel injectors
  • In need of a tune up

 

First things first:

Check to make sure your gas cap is on and give it a few more clicks to tighten it up. If that doesn’t work, head to ADVANCED AUTO DIAGNOSTICS, it’s always a good idea to get a professional to diagnose the problem.  A few of the above items are inexpensive to fix. While others are more expensive, it’s still important to get them taken care of. Even though the car could be driving just fine, you may be wasting fuel, putting out lots of pollution and damaging the engine. One sign of immediate attention is if the check engine light is flashing on and off. This is telling you that the problem is in need of urgent attention before major damage is done.

Whatever you do, don’t lazily slap a piece of black electrical tape over it and go about your business. Cars just need a little love from time to time to stay in good shape, and neglecting a minor issue could lead to bigger problems down the road.

The check engine light is one of the most frustrating and confusing facets of owning a vehicle. It’s just a light with no information telling you what the problem is.

Unless your car starts smoking or stalls completely head over to ADVANCED AUTO DIAGNOSTICS and have our service technicians run a diagnostic to find the cause of the check engine light. Once here we will plug a computer underneath your dashboards OBD connector and read back a code stating what is going on with your vehicle. Which than will give us some direction on which components need to be tested to find the problem. If your vehicle is stalling or simply shut off take advantage of our commercial accounts with our private towing companies to get you over to the shop at a reasonable price.

Five common malfunctions cause the check engine light to come on:

 

One: Replace Oxygen Sensor

An oxygen sensor is a part that monitors the unburned oxygen from the exhaust. It helps monitor how much fuel is burned. A faulty sensor means it’s not providing the right data to the computer and causes a decrease in gas mileage. Most cars have between two and four oxygen sensors.

What causes it: Over time, the sensor gets covered in oil ash and it reduces the sensors ability to change the oxygen and fuel mixture. A faulty sensor not only reduces gas mileage, it also increase emissions.

What you should do: Not replacing a broken oxygen sensor can eventually lead to a busted catalytic convertor which can increase cost of repairs

 

Two: Loose or Faulty Gas Cap

You wouldn’t think a gas cap would be that important, but it is. When it’s loose or cracked, fuel vapors leak out and can throw the whole fuel system off. This causes a reduction in gas mileage and increases emissions.

What causes it: If you get an error pointing to the gas cap it means fuel vapors are leaking out of your cap. This means the cap is either cracked or just wasn’t tightened well enough.

What you should do: If your car isn’t feeling jerky or strange when the check engine light comes on, first you should check that the gas cap is on. Pull over, retighten it, and take a look at the cap to see if it has any cracks in it. Continue driving and see if the check engine light turns off.   If tightening the gas cap does not resolve the issue, come to ADVANCED AUTO DIAGNOSTICS to diagnose your problem.

 

Three: Replace Catalytic Convertor

The catalytic convertor works to reduce exhaust gases. It converts carbon monoxide and other harmful materials into harmless compounds. If your catalytic convertor is failing, you’ll notice a decrease in gas mileage or your car won’t go any faster when you push the gas.

What causes it: Catalytic convertors shouldn’t fail if you’re keeping up on regular maintenance. The main cause of failure is related to other items on this list, including a broken oxygen sensor or deteriorated spark plugs. When it fails, it stops converting carbon monoxide into less harmful emissions.

What you should do: If your catalytic convertor fails completely, you eventually won’t be able to keep the car running. Your gas mileage will also be terrible, so you should try and fix it as soon as you can.

 

Four: Replace 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. A faulty one can increase emissions, cause the car to stall, and decrease gas mileage.

What causes it: Most mass airflow sensors fail because of an improperly installed (or never replaced) air filter. You should replace the air filter at least once a year to help prevent the airflow sensor from failing.

What you should do: You will notice a decrease in gas mileage and over time the car will eventually start stalling a lot bring it in to Advanced Auto Diagnostics and we will let you know what the most cost effective solution is.

 

Five: Replace Spark Plugs and or Ignition Coils

The spark plug seals the combustion chamber and provides a gab for a spark to jump across and initiates combustion in your engine. When the Ignition Coils are failing, the spark plugs misfire. You’ll feel a little jolt in your car’s acceleration when this happens and lack of power. In some vehicles the vehicle will go into a safe mode and indicate lack of power in order to prevent damage to the engine and catalytic. Check engine light might also start flashing on and off.

What causes it: Most spark plugs in cars should be replaced every 25,000 to 100,000 miles depending on the type of plug used. Still, plugs fail over time and there’s not much you can do about it. More common are direct ignition coils that fail to send the electrical power through the spark plug.

What you should do: Get them replaced right away. If your spark plugs fail and you’ve made your way to ADVANCED AUTO DIAGNOSTICS, have them checked to determine the proper course of action to repair.

Plenty of other possibilities for a check engine light are out there, but the above five are the most common.