How to Reset Service Engine Soon Light: A Comprehensive Guide

To reset the “Service Engine Soon” light, you can try disconnecting the car’s battery for about 10-15 minutes, which may clear the light. Alternatively, you can use an OBD-II scanner to read and clear the error codes that triggered the light. If the light remains on, it could indicate an unresolved issue that requires professional diagnosis.

The “Service Engine Soon” light, also known as the check engine light, is an indicator that your vehicle’s onboard diagnostics system has detected an issue. This warning light doesn’t necessarily mean an immediate mechanical failure, but it’s a sign that something needs attention. The issue could be as minor as a loose gas cap or as significant as a malfunctioning engine component. Understanding what triggers the light and how to reset it properly is crucial for both the longevity of your car and your peace of mind.

In this blog, we’ll walk you through the steps to reset the “Service Engine Soon” light, explore the reasons why it turns on, and explain when a DIY reset might be appropriate. Additionally, we’ll cover important tips and precautions to ensure you handle this task safely and responsibly.

Why Does the “Service Engine Soon” Light Come On?

Before diving into the steps to reset the light, it’s important to understand why the “Service Engine Soon” light may illuminate in the first place. This light comes on due to various reasons, including but not limited to:

1. Loose or Faulty Gas Cap: One of the most common and simplest reasons for the light to turn on. A gas cap that isn’t tight or is damaged can cause the onboard computer to detect an evaporation leak.
2. Oxygen Sensor Issues: The oxygen sensor measures the amount of unburned oxygen in the exhaust system. If it fails, your car’s engine performance may drop, and your fuel efficiency will suffer.
3. Malfunctioning Catalytic Converter: This component reduces harmful emissions by converting carbon monoxide into carbon dioxide. If it’s not functioning properly, the “Service Engine Soon” light may come on.
4. Faulty Mass Airflow Sensor: The mass airflow sensor monitors the amount of air entering the engine and determines how much fuel to inject for optimal performance. A failure in this sensor can lead to engine stalling or poor fuel economy.
5. Ignition Coil or Spark Plug Issues: Misfires caused by worn spark plugs or ignition coils can also trigger the light.
6. Emission Control System Issues: Problems with the emission control system, such as the evaporative emissions system (EVAP), can trigger the “Service Engine Soon” light.

In many cases, addressing these issues will turn off the warning light automatically. However, after the issue is resolved, or if the light is still on after maintenance, resetting it may be necessary.

How to Reset Service Engine Soon Light: Step-by-Step Guide

While it’s tempting to simply reset the light and forget about it, it’s crucial first to diagnose and fix the underlying issue. Resetting the SES light without addressing the root cause is akin to ignoring a medical diagnosis—temporary relief, but the problem persists.

Here’s how you can reset the light, but remember, this is not a substitute for proper maintenance.

Method 1: Using an OBD-II Scanner

The most reliable and effective way to reset the “Service Engine Soon” light is by using an OBD-II (On-Board Diagnostics) scanner. This device can read the diagnostic codes and clear them after the problem is fixed.

Step 1: Purchase or Borrow an OBD-II Scanner

You can find OBD-II scanners at most auto parts stores or online. Many mechanics may let you borrow theirs if you ask. Some even provide free diagnostic checks and resets.

Step 2: Locate the OBD-II Port

The OBD-II port is typically located under the dashboard on the driver’s side, near the steering column. If you’re having trouble finding it, check your vehicle’s owner manual.

Step 3: Plug in the Scanner

Insert the OBD-II scanner into the port. Turn the vehicle to the “ON” position, but don’t start the engine.

Step 4: Read the Diagnostic Codes

Most scanners will automatically retrieve the error codes from your vehicle’s computer. Write these codes down for reference.

Step 5: Fix the Underlying Issue

It’s crucial to fix the problem indicated by the error code before resetting the light. Resetting it without addressing the issue may result in the light coming back on soon after.

Step 6: Clear the Codes

After fixing the issue, use the scanner’s option to clear or erase the codes. The “Service Engine Soon” light should turn off once this is done.

Method 2: Disconnecting the Battery

If you don’t have access to an OBD-II scanner, you can reset the light by disconnecting the battery. This method effectively resets the car’s computer, erasing the codes in the process.

Step 1: Open the Hood

Ensure the vehicle is off before proceeding. Open the hood and locate the battery.

Step 2: Disconnect the Negative Battery Cable

Using a wrench, loosen the nut on the negative battery terminal (marked with a minus “-” sign) and carefully remove the cable. Wait for about 10-15 minutes to allow the vehicle’s electrical system to reset.

Step 3: Reconnect the Battery

Reattach the negative battery cable and tighten the nut securely. Close the hood and turn on the ignition. The “Service Engine Soon” light should now be off.

Step 4: Drive the Vehicle

Take your car for a short drive to ensure everything is functioning correctly. If the light comes back on, it means the underlying issue hasn’t been resolved.

Method 3: Resetting Through the Ignition Key

Some vehicles allow you to reset the “Service Engine Soon” light using only the ignition key, especially older models.

Step 1: Turn the Key to the “ON” Position

Insert the key into the ignition and turn it to the “ON” position (just before cranking the engine).

Step 2: Turn the Key Off and On

Turn the key off and then back to the “ON” position three times in quick succession. On the third time, leave it in the “ON” position. This action may reset the “Service Engine Soon” light.

Step 3: Start the Engine

After the third cycle, start the engine. The light should be off, indicating the reset was successful.

Method 4: Letting the Car Reset Itself

In some cases, the “Service Engine Soon” light will reset itself after a certain number of driving cycles, provided the underlying issue has been fixed.

Step 1: Fix the Problem

Make sure the issue that triggered the light is fully resolved.

Step 2: Drive the Car

Continue driving the car normally for several trips. Depending on the car, it may take 10-20 cycles (start-up and shut-down sequences) for the light to reset itself.

Step 3: Monitor the Light

If the light doesn’t turn off after a reasonable amount of time, there may still be a problem, and professional diagnostics are recommended.

Important Considerations and Precautions

• Don’t Ignore the Warning: The “Service Engine Soon” light is a sign that something in your vehicle needs attention. Ignoring the warning can lead to more significant issues or costly repairs in the future.
• Professional Help: If you’re unsure about what’s causing the light to turn on or if the issue seems serious, it’s best to seek professional assistance. A mechanic can diagnose the issue and reset the light safely.
• False Positives: Occasionally, the light may turn on due to a minor glitch in the system, such as a temporary sensor issue. However, always check the issue before assuming it’s a false alarm.

Frequently Asked Questions

Here are some FAQs about resetting service engine soon light –

1. What does the “Service Engine Soon” light mean?

The “Service Engine Soon” light typically indicates a minor problem with the vehicle’s engine or emissions system. It can also be a reminder for routine maintenance. However, it’s not as severe as the “Check Engine” light, which indicates a more significant issue.

2. Can I reset the “Service Engine Soon” light without fixing the problem?

Technically, yes. You can reset the light, but the underlying issue will still exist. The light will likely come back on until the problem is resolved. It’s always best to fix the issue before resetting the light.

3. Is it safe to drive with the “Service Engine Soon” light on?

It depends on the underlying cause. If the light is due to a minor issue like a loose gas cap, it’s generally safe to drive. However, more serious issues like problems with the catalytic converter or oxygen sensors can affect your car’s performance and emissions. Always diagnose the issue as soon as possible.

4. Will disconnecting the battery damage my car?

Disconnecting the battery will not harm your car, but it will reset all the electronic systems, including the radio presets, clock, and other customized settings. It’s also not a permanent fix if the underlying issue remains.

5. How long does it take for the “Service Engine Soon” light to reset on its own?

If the issue has been resolved, the light may reset itself after 10-20 driving cycles. However, if the light stays on after this period, further investigation is needed.

Conclusion

The “Service Engine Soon” light serves as a helpful alert that something in your car requires attention. While resetting the light is straightforward, addressing the underlying cause is essential to prevent long-term damage to your vehicle. Whether you use an OBD-II scanner or try other methods, always ensure that any issues are fixed before attempting to reset the light. If in doubt, consulting with a professional mechanic is always the best approach to ensure your vehicle runs safely and efficiently.