Definition and What to Do

You may see a variety of warning lights as you drive along the roads, but none are necessarily good. The Malfunction Indicator Lamp (MIL) is what seems to be the most bothersome. It’s important that you know what to do when the Malfunction Indicator Light Illuminates, so you can get back on the road with peace of mind. 

We will be covering the basic functions of the Malfunction Indicator light in this guide. This guide will also discuss the next steps to take if it turns on, as well as possible repairs costs. 

What's the Malfunction Indicator Lamp (MIL), and how can it be used?

Technically, the Check Engine Light is called the Malfunction Indicator Light (MIL). It’s a warning light that comes on the dashboard to tell you when there’s a system malfunction. It’s the ECU’s way of alerting you to potential trouble. After a number of tests to ensure that nothing is outside its limits, the light will turn on.

Malfunction Indicator light may come on for a trivial reason, such as loose gas caps. Sometimes it indicates a more serious problem, like a loose gas cap. OBDII codes scanners are the only way you can decode the issue. 

What to do when Malfunction Indicator light (MIL) illuminates

Any signs of trouble should be avoided if your MIL is stable and constant. The OBDII Code scanner should be used to scan the DTC codes. If the Check Engine Light is blinking, pull the car over and don’t drive it until the diagnostics are complete. 

1. Solid light

Multiple issues could cause the Check Engine Light to come on or stay on. It could also be an obvious fault, like not having the gas cap removed when you last filled your tank. It’s wise to give your car a quick inspection to see if something noticeable is to blame. You can quickly fix the issue and get on with your life.

However, if you don’t spot an immediate issue, you will need to pay close attention to any other symptoms that are occurring. Is there any trouble with your performance? Do you notice any strange smells? Are you hearing the car vibrating or shaking? All of these answers will help you get to the bottom of what’s happening.

It’s also wise to take note of any other lights that came on at the same time. Some faults will cause more lights than necessary to pinpoint the problem. If both the Oil Pressure Light and Check Engine Light turn on simultaneously, it is likely that the oil pressure problem is serious. The Check Engine Light will turn off if you fix the light that is first. 

This information will be used in combination with any DTC scan results. Connect your OBDII scanner to the port, and you will be able to read all engine codes. You can also erase any that you don't want to be read and then take your car on a test drive in order to reset them all. These codes will help you pinpoint the problem and fix it. 

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2. Flashing light

It is important to not walk on flashing Malfunction Indicator Lamps the same way as you would when they come on slowly. The flashing Malfunction Indicator Lamp is trying to grab your attention. It would be wise for you to pay close attention. To begin, make sure you pull your car over at a safe place. The flashing light could lead to more damage.

You can scan the DTCs with a code scanner to determine what the issue is. You might have to tow your vehicle to an authorized repair facility for additional assistance. 

READ MORE: Engine light flashing? (Here’s What to Do)

How to turn off the Malfunction Indicator Lamp (MIL).

The Check Engine Light doesn’t turn itself off until the problem that triggered it is repaired. Some vehicles have an intermittent fault which needs to be fixed for the check engine light to turn off. If the problem codes persist, it is best to use your scanner to clear them.

READ MORE: Can the check engine light reset itself? What if it doesn't?

Older vehicles can be disengaged from the battery in order to free up memory. This would then turn the light off. However, the Check Engine Light always comes back on if the problem isn’t repaired. Plus, pulling the battery can also cause some annoyances that aren’t worth dealing with. 

Before you clear any codes, consider if that’s the best option. Clearing out old codes can cause you to lose vital data which will be useful in troubleshooting the issue. Erase older codes if you have to keep an eye on the problem for a specific time in order to fix it. You might have to wait for new data before you can get the heart of what’s going on. Instead, you want to read through the old codes first and try to decipher what’s happening. 

RELATED : Resetting a Check Engine light (5 Simple Methods).

You can only fix the Malfunction Indicator Light problem to make it go away. Once the fix is complete, you can reset the codes and the light shouldn’t come back on. If the light comes on again, it is time to start diagnosing. 

It costs to switch off Malfunction Indicator lamp (MIL).

There are two main factors that affect how much it costs to repair the Malfunctioning Indicator lamp (MIL). The first is that the cost of repair directly correlates with what has to be done. Secondly, your cost will change dramatically if you don’t have a code scanner and/or you need a professional to repair the problem. 

For the sake of this article, let’s assume that you need to have a professional fix the Malfunctioning Indicator Lamp. These are some possible problems and approximate costs to fix them. 

1. 25-$75 to tighten, replace or repair a broken or loose gas cap
2. Replace malfunctioning oxygen sensor: $150-$450
3. Replacing damaged catalytic converts: $1500-$3,500
4. Spark plugs and ignition coils can be replaced for $250 to $450
5. Replace ignition coils $150-$450
6. Replacement thermostat: $200-$400
7. Replacement mass airflow sensor $250-$450
8. Replace fuel injector: $300-$750
9. Purge control valve to replace evaporative emission (EVAP), $110 to $2275

The car type you drive will have a significant impact on the cost of repairs. Common vehicles, like a Chevy and Dodge, may have parts less costly than luxury cars such as Mercedes-Benz or Audi. While you can get most technicians to fix your standard vehicles, it might take someone with special skills to do repairs on your BMW or another foreign import. For this reason, it’s difficult to give an accurate estimate of what the repair might cost.

One way you can save money is to visit a local auto parts store if you don’t have your own code scanner. These stores can scan your computer to give you codes for no cost. Although you can still do some research on your own to find the root cause, it will help to reduce the cost of diagnostics.

READ MORE: Check Engine Light Is On But No Codes – Causes & What to Do?