Why is your Toyota Fortuner check engine light on?

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Introduction to check engine light

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On the instrument panel of every car sold in the United States since the middle of 1980s, the check light is connected to OBD2 scanners or car diagnostic tools. These monitor the car engine as well as other systems like the emissions control.

The computer automatically turns on the check engine light in case a diagnostic sensor reading is not within a specified range. Also, the computer will capture a code that identifies the bad reading.

Computer monitoring by the use of OBD (on-board diagnostic) processors started in the 1980s. There is the Clean Air Act of 1990, which mandates that every vehicle sold in the USA after 1995 must be equipped with an on-board diagnostic system with the use of an established set of codes.

In the industry, the system is known as OBD2 (second-generation on-board diagnostic). The codes that are captured by an OBD2 computer can be deciphered by a code scanner.

Whether OBD2 compliant or utilizing the non-standardized, older OBD1 protocol, the diagnostic system will continuously monitor an array of sensors. If or when a sensor reading finds something not good, the OBD computer turns on the “Check Engine” light. It will then store a five-character code in its memory.

Why is Your Toyota Fortuner Check Engine Light On?

Regular maintenance of your vehicle is a significant aspect of owning a Toyota. It can help you prevent undesired stress in the long run. In case you’ve ever had the check engine light blink on while driving, you’ll know what it means.

The feared check engine light being on can create instant stress or panic, which is followed by a question: Why is the check engine light on? Guard your automotive investment by combatting this issue before it even becomes more consequential by comprehending the main reasons why your vehicle’s check engine light is on.

1. Bad O2 Sensor

If in case your check engine’s light is on, there is a possibility that you have a defective oxygen sensor, which requires a replacement. This engine component quantifies the amount of unburned O2 in your vehicle’s exhaust system.

If it is not replaced, this can result to damaged spark plugs, decreased fuel-economy ratings, excess fuel burn and a degenerated catalytic converter.

2. Damaged or Loose Gas Cap


A well-sealed gas cap retains pressure in your vehicle’s fuel tank and it prevents damaging fumes from breaking out. If you do have a damaged or loose gas cap, you will not only have your check engine light turn on, but you can also lose fuel by evaporation.

As an easy and quick fix, ensure to check the gas cap if your car’s check engine light turns on.

3. Bad Catalytic Converter


Created to guard the environment through turning carbon monoxide into carbon dioxide, a catalytic converter that does not function well is typically indicated by your car’s check engine light. This component when damaged is commonly because of no maintenance.

With a catalytic converter that is not good, you’ll not be able to pass the emissions test, you may run at a heightened temperature and you’ll see a decline in performance in your car. Stop in today at any Toyota Service Department and they will check it for you.

4. Bad Mass Airflow Sensor


Another component you may have to check if the check engine light illuminates is the mass airflow sensor. This monitors the amount of air circulating in your car’s engine. This aids in determining how much fuel is necessary for your car to run efficiently.

A bad mass airflow sensor can obstruct performance, and it can also create damage to your O2 sensor, catalytic converter and spark plugs if it is not replaced.

5. Bad Spark Plug Wires or Spark Plugs

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Essential components of your car’s engine, the spark plugs ignite the mixture of fuel while spark plug wires relay that energy to the engine. If these crucial elements are bad, it may be pointed out by the check engine light. If is not resolved quickly, it can result to decreased power as well as fuel economy.

Moreover, it can damage the other components. In case the check engine light illuminates in your Toyota Fortuner, ensure to examine the condition of its spark plug wires and spark plugs.

Is it safe for you to drive with the car’s Check Engine light on?

While it is understood that not everyone is a born mechanic, understanding why your car’s check engine light illuminates can relieve you from a lot of stress. In case that stressful little light does appear, it’s important to bear in mind to not panic. Just get your car serviced ASAP to avoid lasting damage.

Your car’s Check Engine Light is connected to the emissions system, and it is designed to flicker whenever there is something bad with this complicated collection of sensors and components.

If in case it turns on while you’re driving, it can be daunting. But don’t panic. Take notice if the vehicle is running any differently than it normally does. Is it surging or bucking? Do you hear any unusual sounds?

In case nothing seems to be unusual, you can keep on driving your car. It could be just anything from a bad MAF sensor to a failed oxygen sensor. Or, it could mean that the catalytic converter has already given up the ghost.

Notwithstanding, you are safe to drive for now – that is, if your car is not performing out of the ordinary. Have the Check Engine Light examined and the issue resolved. Not fixing the problem can result to more serious problem down the road (i.e., a failed oxygen sensor can result to catalytic converter damage after some time, and it’s far more pricey to replace).

If the light turns on after fueling up, it may have a loose gas cap – this is for many present models. For older models, it did not come with this feature. In case you left your gas cap off or loose, the computer automatically detects a leak in the car’s evaporation emissions system and thus turns on your Check Engine Light.

So, if the light illuminates shortly after you fueled up, check the gas cap, take it off again and then put it back securely. Drive your car for a little while and check if the light flickers. (Note that it could take a couple of restarts of your engine to turn the light off).

If your vehicle’s Check Engine Light is still on, this means that there is a problem somewhere in the emissions system. A mechanic can examine the codes, which are stored in your car’s computer. He will make some recommendations and/or even provide part replacements or repairs.

What are your repair options?

• Dealership

• Brand-specialized shops

• Independent repair shops

• Checking the car and repair it yourself with an OBD2 scan tool


A Check Engine light that is on is often a general warning that your Toyota Fortuner must be serviced ASAP. Consult your manual for some specific instructions. Without a blink code reader or an OBD2 scanner, it’s mostly impossible to know the problem or how severe it is.


About the author

http://www.obdadvisor.com/wp-content/uploads/2017/03/1907226-2.jpg I’m Tim Miller, an automotive mechanic and blogger from Denver, Colorado. I’m the founder of obdadvisor.com, an automotive blog about OBD2 scan tools.

I’ve had over 10 years experience in car repair and using OBD scanners.

Some of my review articles about car diagnostic tools can be found on my own website obdadvisor.com.


3 Comments on "Why is your Toyota Fortuner check engine light on?"

  1. Thank you Tim, very informative. This happened to me twice and along with the Check Engine light on, the Slip Indicator light also went on and engine stopped. After some time, as I searched the manual, there was no explanation nor remedial action that I could take. Started the engine and went home driving slow and called for the Toyota mechanic to pick up the car. Is there a way we can be less stressed out by installing our own OBD tool?

  2. aurelio gumasing | April 17, 2020 at 11:31 am | Reply

    after cleaning my egr.. why car does nt start but i is cranking with new battery.
    please help me

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