This indicator is part of the onboard diagnostics (OBD-II) system and in all cases it indicates a problem with your emissions system. Basically, it is an emissions monitoring system. A Check Engine indictor will stay solid or blink.
- If the indictor is blinking, the situation is usually serious, such as a severe misfiring of the engine. This would allow unburned fuel to dump into the exhaust system, pushing the temperature of your catalytic converter to the breaking point. Slow the car down, find a safe place to stop, and request a mechanic to perform a diagnosis.
- A steady light on the other hand is not an emergency situation. You can continue driving, but you should schedule an appointment with a mechanic as soon as possible.
Possible Root Causes:
While a Check Engine Light can come on for a number of reasons, in most cases it is due to one of the following issues:
- Loose or damaged fuel filler cap: It’s hard to believe that a fuel filler cap can prompt your check engine light to come on, but it can. Your fuel filler cap acts as the seal for your fuel system and it helps maintain the pressure in your fuel tank. A loose or damaged cap can reduce your fuel mileage and increase emissions from your car.
When that annoying yellow light pops on, the first thing you should do is pull over and inspect your fuel filler. If it is loose, a quick tighten could very well solve your problem. If it is damaged, you will need to get it replaced.
Once you have fixed the issue, continue driving to see if the check engine light turns off. If the light stays on, have the vehicle inspected.
- Faulty oxygen sensor: An oxygen sensor monitors the exhaust for unburned oxygen, which indicates engine efficacy and the proper air-to-fuel ratio. If you have a faulty sensor, it will not provide the correct data to the onboard computer. The majority of vehicles have two to four sensors. The OBD II code will tell the technician which one is giving a reading that is outside of its parameters.
Deterioration of the precious metals inside the oxygen sensor affects the sensors’ ability to give an accurate reading. If you put off getting an oxygen sensor replaced, it will eventually damage your catalytic converter, which can be very costly to replace.
- Failing catalytic converter: A catalytic converter helps reduce emissions in the exhaust gases. It converts the carbon monoxide and other harmful gases into less harmful emissions. A failing converter will negatively affect your gas mileage and when the damage becomes severe enough, your vehicle won’t go any faster when you push down harder on the accelerator pedal.
In most cases, a catalytic converter will not fail if you properly maintain your car. A failing converter can be the result of a faulty oxygen sensor that has not been replaced or any other engine efficacy issue.
A faulty catalytic converter will eventually bring your car to a complete stop. Before that, your gas mileage will be poor, the car will not run smoothly, and the car will not pass an emissions test. A damaged converter should be replaced immediately.
- Faulty mass airflow sensor: This part directs the computer in your vehicle to add the correct amount of fuel based on the air that is coming through the engine. When a mass airflow sensor starts to fail, the car will stall, it will idle poorly, the emissions will go up, and your gas mileage will go down.
An air filter that has never been replaced or improperly installed can sometimes be the culprit when it comes to a faulty mass airflow sensor. Have your air filter checked and replaced on a yearly basis.
While it is possible to drive for months with a malfunctioning mass airflow sensor, it’s not a good idea. Your gas mileage will drop and the car will start stalling frequently. It is best to call a mechanic and have the sensor diagnosed and replaced if necessary.
- Bad spark plugs and wires (petrol engines): A spark plug acts as a seal in the combustion chamber and provides the gap for the spark that causes combustion in the engine.
There is no way to prevent spark plugs from failing, it just happens over time. If spark plugs are your issue, get them replaced immediately.
How it’s done:
When the Check Engine Light is on, your car’s monitoring system will have “fault codes” that indicate the nature of the problem. Your car may have one or more problems and hence there can be multiple codes.
The mechanic will read the codes using a scanner, interpret the codes, and provide a diagnosis. If you approve the repair estimate, they will replace the faulty part(s), clear the memory of any fault codes, turn the Check Engine Light off, and let you drive the car for a few days to see if the light comes back on or not.
Please note: It may take several days of driving the car for the monitoring system to verify that the repair has fixed all the problems. If the monitoring system fails any of its internal tests, it will turn the light back on. This means that the car has more problems that were not evident during the first evaluation. The mechanic will have to perform further diagnosis and create new repair estimates for resolving the problems found. In some rare cases, multiple visits may be required to diagnose and resolve the stubborn Check Engine Light issues.
How important is this service?
A blinking Check Engine Light indicates a critical issue, whereas a solid light reflects a non-emergency situation. Once you rule out a loose fuel filler cap, the next step is to accurately diagnose the issue as soon as possible.