Experiencing the sudden illumination of the check engine light in your vehicle can be a source of anxiety and concern, particularly if it happens shortly after an oil change. You might find yourself wondering what could trigger this unwelcome warning. After all, an oil change is typically considered routine maintenance, so why would it lead to the check engine light coming on?

A sign that something is amiss with your vehicle’s functioning is when the check engine light is on. Its activation often implies the presence of a significant issue, though there are instances where a loose gas cap can cause it to illuminate. However, under normal circumstances, a recent and correctly executed oil change should not be the direct cause of the check engine light appearing.

Let’s delve into the reasons why the check engine light may illuminate after an oil change:

Lack of Oil Pressure

Properly conducting an oil change should not trigger the check engine light, at least not temporarily. During an oil change, the oil is drained from your car’s engine, which also resets the oil pressure gauge. When you replace the oil and install a new filter, it takes some time for the gauge to provide an accurate reading. As a result, the check engine light might illuminate because the vehicle “believes” it is low on oil. Allowing a few minutes for the oil pump to distribute the new oil throughout the engine should resolve this issue and extinguish the check engine light.

Misaligned Gas Cap

Occasionally, the cause of the check engine light coming on may not be linked to the oil change, although initially, it may appear that way. Modern cars are equipped to detect issues such as a loosely or incorrectly secured gas cap. If you filled the fuel tank after your oil change and didn’t properly secure the cap on the gas tank, that may be why the check engine light is on. To address this, check your gas cap, ensure it is securely tightened, and wait a few minutes after starting the engine to see if the issue resolves.

Even if the cap is on it could be broken or cracked and that might be the root cause. A properly functioning gas cap maintains fuel pressure, facilitates fuel flow into the engine, and prevents fuel vapors from escaping. If the gas cap fails to create a proper seal, it can lead to the activation of the check engine light.

Unreset Oil Sensor

After an oil change, it’s essential to reset the oil sensor if your vehicle allows for it. Failing to reset the sensor can result in the check engine light illuminating. Here are two methods to reset the check engine light:

Method 1:

Turn the ignition key without starting the engine. Wait for all the indicator lights to come on. Locate the “reset” stick, typically found between the speedometer and tachometer. Press it until the light blinks, indicating a successful reset. Remove the key, reinsert it, and start the car. The check engine light should be off if no other issues exist.

Method 2:

Try this approach if the previous method doesn’t work. Repeat step 1 from the previous method. Quickly depress the gas pedal three times within a five-second window. The light should be reset and remain off after the engine has been started.

If neither of these methods works, you may need to locate your vehicle’s fuse box, where you can find a reset button. Press this button until you hear a beeping sound to reset the check engine light.

Incorrect Oil

Another possible culprit is using the wrong type of oil. Oil has weight, grade and viscosity. Your vehicle may require 5w-40 oil, if you were to mistakenly use 0w-40 oil because you believe they are interchangeable can lead to issues. Inadequate lubrication and heat transfer can result from using excessively viscous oil, causing the oil to heat up excessively and triggering the check engine light. In such cases, you should drain the oil, replace the oil filter, and use the correct grade of oil as recommended for your vehicle.

In conclusion, while it is uncommon for an oil change to cause the check engine light to illuminate directly, there are specific circumstances where it may appear to be related. Typically, this occurs due to a misaligned gas cap, an unreset oil sensor, or incorrect oil use. To rectify the issue, ensure the gas cap is seated correctly, reset the oil sensor as needed, use the appropriate oil grade, and restart the engine up to three times to clear the check engine light.