The Check Engine Light is one of the most commonly illuminated warning lights on modern vehicles. While it can be an unwelcome sight, it’s a critical way for your vehicle to alert you to potential issues that need to be addressed. Many drivers want to know how to reset the Check Engine Light once any problems have been identified and resolved. This comprehensive guide will walk you through the proper steps for safely and effectively resetting the light to get it turned off.
Understanding the Check Engine Light
Before getting into how to reset it, it’s important to understand what the Check Engine Light actually is and what causes it to come on. The Check Engine Light is officially known as the Malfunction Indicator Lamp (MIL), and it’s a critical component of your vehicle’s onboard diagnostic (OBD) system.
The OBD system continuously monitors the performance and operations of many of your vehicle’s major components and systems, including:
- – Engine
- – Transmission
- – Catalytic converter
- – Fuel and air metering systems
- – Emissions controls
When the OBD system detects a problem with one of these monitored systems, it triggers the Check Engine Light and records a diagnostic trouble code (DTC) that corresponds to the specific issue detected.
What Causes The Check Engine Light to Come on?
There are many potential reasons that can cause a vehicle’s Check Engine Light to illuminate. Here are some of the most common culprits:
Loose or Faulty Gas Cap
One of the simplest things that can trigger the light is having a loose, cracked, or damaged gas cap. This allows fuel vapors to escape from the fuel tank, setting off the evaporative emissions monitoring system.
Oxygen Sensor Failure
The upstream and downstream oxygen sensors monitor the air/fuel mixture going into and out of the engine. A failed oxygen sensor will cause an improper mixture, triggering the light.
Catalytic Converter Issues
The catalytic converter is a key emissions control component. If it becomes clogged or stops working efficiently, it can no longer properly convert harmful exhaust gases, setting off the Check Engine Light.
Spark Plug/Ignition Coil Problems
Faulty spark plugs that are fouled or worn out, or bad ignition coils that supply voltage to the plugs, can cause misfiring issues that trip the light.
Mass Airflow Sensor Troubles
The mass airflow sensor monitors the air entering the intake system. A failed sensor will cause an incorrect air/fuel ratio and turn on the light.
Exhaust Leaks
Even a small crack or hole in the exhaust system can allow unburnt fuel to escape, causing the emissions monitors to detect a problem.
Thermostat Failure
A stuck open or closed thermostat will prevent the engine from reaching and maintaining its optimal operating temperature, throwing a code.
While there are many other potential causes, those are some of the most frequently seen issues that will illuminate the Check Engine Light. The only way to know for sure is to have the specific diagnostic trouble code read and diagnosed properly.
Also Read: How to Test Ignition Coil: A Comprehensive Guide and Symptoms of a Bad MAP Sensor
Steps For Resetting the Check Engine Light
1. Using an OBD-II Scanner
An OBD-II scanner is a professional-grade tool used for diagnosing and resetting the check engine light. Here’s how to use it:
- Locate the OBD-II Port: The OBD-II port is typically located under the dashboard near the steering column.
- Connect the Scanner: Plug the OBD-II scanner into the port.
- Turn the Ignition On: Switch the ignition key to the “on” position without starting the engine.
- Read Diagnostic Trouble Codes (DTCs): Use the scanner to read any stored DTCs.
- Clear the Codes: Follow the scanner’s instructions to clear the DTCs and reset the check engine light.
2. Disconnecting the Battery
Resetting the check engine light by disconnecting the battery is a simple DIY method. Here’s how to do it:
- Turn Off the Engine: Ensure the engine is completely turned off.
- Locate the Battery: Open the hood and locate the vehicle’s battery.
- Disconnect the Negative Terminal: Use a wrench to loosen the nut on the negative terminal (-) of the battery.
- Wait for 15 Minutes: Leave the battery disconnected for at least 15 minutes to reset the vehicle’s electrical system.
- Reconnect the Battery: Tighten the nut on the negative terminal to reconnect the battery.
3. Driving and Time Method
In some cases, simply driving the vehicle for a certain distance or through specific conditions can reset the check engine light. Here’s how it works:
- Drive Normally: Drive your vehicle under normal conditions for a few days.
- Complete Driving Cycles: Some vehicles require specific driving cycles (combination of city and highway driving) to reset the check engine light.
When to Seek Professional Diagnosis/Repair
While some vehicle owners are comfortable tackling basic maintenance and repairs themselves, more complex issues are best left to an experienced professional mechanic. Here are some instances where you may want to skip the DIY and go to the pros:
- – Check Engine Light remains illuminated after your attempted reset
- – You are unable to retrieve/understand the diagnostic trouble code(s)
- – The issue seems to be related to major components (engine, transmission, emissions, etc.)
- – You aren’t confident troubleshooting/repairing the diagnosed problem area
A trained mechanic has access to specialized tools and knowledge to properly diagnose and repair even the most complicated Check Engine Light issues efficiently and correctly.
Also Read: Symptoms Of A Bad Ball Joint and How to Replace Tail Light Bulbs: A Comprehensive Guide
Conclusion
While illumination of the Check Engine Light can be an unwelcome surprise, it is a critical way for your vehicle to alert you to issues that need to be addressed. By promptly diagnosing issues using an OBD scanner or professional mechanic, making necessary repairs, and then resetting the light using one of the methods above, you can get your vehicle back into tip-top operating condition. Taking proactive maintenance steps to prevent future problems is also wise for optimizing your vehicle’s performance, longevity, and value over the long run. Don’t ignore that Check Engine Light – get it properly reset as soon as possible.