Resetting the check engine light on a 2015 Honda Accord is simple once you understand the root cause. This guide walks you through safe methods—from using an OBD2 scanner to battery disconnection—while stressing the importance of fixing the underlying issue first.
Key Takeaways
- Diagnose before resetting: Always scan for trouble codes to identify and fix the real problem causing the light.
- Use an OBD2 scanner: The safest and most reliable method to clear codes and reset the light on your 2015 Accord.
- Battery disconnection works—but has risks: Disconnecting the battery can reset the light, but may also erase radio settings and adaptive learning data.
- Don’t ignore the light: A flashing check engine light indicates a serious issue requiring immediate attention.
- Drive cycle matters: After resetting, complete a drive cycle to ensure the system relearns and monitors emissions properly.
- Keep records: Save scan reports and repair receipts for future reference or resale value.
- When to see a mechanic: If the light returns quickly, there’s likely an unresolved mechanical or sensor issue.
How to Reset Check Engine Light on 2015 Honda Accord
The check engine light on your 2015 Honda Accord can be alarming—especially if it comes on unexpectedly. But don’t panic. In many cases, it’s a simple fix. However, before you reset the light, it’s crucial to understand why it turned on in the first place. Resetting the light without addressing the underlying issue is like turning off a smoke alarm while your kitchen is still on fire.
This comprehensive guide will walk you through everything you need to know about resetting the check engine light on your 2015 Honda Accord. You’ll learn safe, effective methods—from using an OBD2 scanner to disconnecting the battery—and discover why diagnosing the problem is the most important first step. Whether you’re a DIY enthusiast or just want to save a trip to the mechanic, this guide has you covered.
By the end, you’ll know how to reset the light, understand what the codes mean, and avoid common mistakes that could cost you time and money.
Why the Check Engine Light Comes On
Visual guide about How to Reset Check Engine Light on 2015 Honda Accord
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Before jumping into reset methods, let’s talk about why the light appears. The check engine light—also known as the malfunction indicator lamp (MIL)—is part of your car’s onboard diagnostics system (OBD2). It monitors engine performance, emissions, and various sensors.
On a 2015 Honda Accord, common triggers include:
– Loose or faulty gas cap
– Oxygen (O2) sensor failure
– Mass airflow (MAF) sensor issues
– Catalytic converter problems
– Spark plug or ignition coil faults
– Exhaust gas recirculation (EGR) valve malfunction
Sometimes, the light comes on due to something as simple as a loose gas cap. Other times, it signals a serious engine problem. That’s why you should never reset the light without first checking the trouble codes.
Tools You’ll Need
To reset the check engine light properly, you’ll need a few basic tools:
- OBD2 scanner: A handheld device that reads diagnostic trouble codes (DTCs). Affordable models start around $20.
- Screwdriver or wrench: For battery disconnection (if using that method).
- Owner’s manual: For locating the OBD2 port and battery terminals.
- Notebook or phone: To record codes and notes.
Most 2015 Honda Accords have the OBD2 port under the dashboard, near the driver’s knee. It’s a 16-pin connector, usually black or gray.
Method 1: Using an OBD2 Scanner (Recommended)
This is the safest and most accurate way to reset the check engine light. It allows you to read the codes, understand the problem, and clear them properly.
Step 1: Locate the OBD2 Port
Sit in the driver’s seat and look under the dashboard, near the steering column. The OBD2 port is typically on the left side, about knee-level. It’s a trapezoid-shaped connector with 16 pins.
If you can’t find it, check your owner’s manual or look for a small cover labeled “OBD” or “DIAG.”
Step 2: Plug in the OBD2 Scanner
Turn the ignition to the “ON” position (but don’t start the engine). Plug the scanner into the OBD2 port. Most scanners will power on automatically.
Wait a few seconds for the device to communicate with the car’s computer.
Step 3: Read the Trouble Codes
Press the “Read” or “Scan” button on the scanner. It will retrieve the diagnostic trouble codes (DTCs) stored in the system.
Common codes for a 2015 Honda Accord include:
– P0420: Catalytic converter efficiency below threshold
– P0171: System too lean (bank 1)
– P0300: Random/multiple cylinder misfire
– P0455: Evaporative emission control system leak
Write down the codes. You can look them up online or use the scanner’s built-in code library.
Step 4: Address the Underlying Issue
Don’t skip this step. Resetting the light without fixing the problem is pointless—it will just come back.
For example:
– If the code is P0457 (loose gas cap), tighten or replace the cap.
– If it’s P0135 (O2 sensor heater circuit), you may need a new sensor.
– If it’s P0301 (cylinder 1 misfire), check spark plugs or ignition coils.
Some issues can be fixed at home. Others may require a mechanic.
Step 5: Clear the Codes
Once the issue is resolved, return to the scanner. Press the “Clear” or “Erase” button. The scanner will send a command to the car’s computer to reset the check engine light.
You should see a confirmation message like “Codes Cleared” or “Reset Successful.”
Step 6: Verify the Reset
Turn off the ignition, wait 10 seconds, then turn it back on. The check engine light should be off.
If it’s still on, either the problem wasn’t fixed, or the system needs time to recheck. Drive the car for a short trip (10–15 minutes) to allow the computer to run its self-tests.
Method 2: Disconnecting the Battery
If you don’t have an OBD2 scanner, you can reset the light by disconnecting the battery. This method forces the car’s computer to reset, clearing stored codes.
However, it’s not recommended as a first choice. It can erase adaptive learning data, radio presets, and climate control settings.
Step 1: Turn Off the Engine and Remove Keys
Make sure the car is off and the keys are out of the ignition.
Step 2: Locate the Battery
Open the hood. The battery is on the right side of the engine bay (passenger side in most U.S. models).
Step 3: Disconnect the Negative Terminal
Use a wrench to loosen the nut on the negative (-) battery terminal. It’s usually black and marked with a minus sign.
Carefully remove the cable and tuck it away from the battery so it doesn’t touch the terminal.
Step 4: Wait 15–30 Minutes
Leave the battery disconnected for at least 15 minutes. This allows the car’s computer (ECU) to fully discharge and reset.
Some experts recommend up to 30 minutes for a complete reset.
Step 5: Reconnect the Battery
Reattach the negative cable and tighten the nut securely.
Step 6: Start the Car
Turn the ignition to “ON” and check if the check engine light is off. Then start the engine.
If the light stays off, the reset was successful. If it comes back on, the original problem still exists.
Method 3: Drive Cycle Reset (Natural Clearing)
In some cases, the check engine light will turn off on its own after the problem is fixed—no tools needed.
This happens when the car’s computer runs a “drive cycle” and confirms that all systems are working properly.
A drive cycle is a specific pattern of driving that allows the ECU to test emissions components.
For a 2015 Honda Accord, a typical drive cycle includes:
– Cold start (engine below 122°F)
– Idle for 2–3 minutes
– Drive at 30–40 mph for 5 minutes
– Accelerate to 55 mph, then decelerate without braking
– Repeat for 10–15 minutes
After completing the drive cycle, the ECU may clear the codes and turn off the light—especially for minor issues like a loose gas cap.
However, this method isn’t reliable for serious problems. Always check codes first.
What to Do If the Light Comes Back On
If the check engine light returns after resetting, it means the underlying issue wasn’t resolved.
Common reasons include:
– Incomplete repair (e.g., gas cap tightened but not fully sealed)
– Intermittent sensor failure
– Wiring issues
– Faulty ECU
Don’t keep resetting the light without fixing the root cause. This can lead to:
– Increased emissions
– Reduced fuel efficiency
– Engine damage
– Failed emissions test
If you’re unsure about the repair, take your car to a trusted mechanic or Honda dealership. They have advanced diagnostic tools and can pinpoint the issue.
Troubleshooting Common Issues
Problem: Scanner Won’t Connect
– Make sure the ignition is on (but engine off).
– Check that the OBD2 port is clean and undamaged.
– Try a different scanner or update the firmware.
Problem: Light Resets But Comes Back Immediately
– The issue is still present. Recheck the trouble codes.
– Look for loose connections or damaged sensors.
– Consider a professional diagnosis.
Problem: Radio or Clock Reset After Battery Disconnect
– This is normal. Re-enter your radio presets and set the clock.
– Some cars require a security code to restore the radio—check your manual.
Problem: Car Runs Rough After Reset
– The ECU may need time to relearn driving patterns.
– Drive normally for 50–100 miles to allow adaptive learning.
– If problems persist, have the engine inspected.
Tips for Preventing Future Check Engine Lights
– Check the gas cap: After every fill-up, make sure it’s tight. A loose cap is the #1 cause of false check engine lights.
– Use quality fuel: Avoid cheap or contaminated gasoline.
– Follow maintenance schedule: Replace spark plugs, air filters, and oxygen sensors as recommended.
– Listen for unusual sounds: Knocking, pinging, or rough idling can signal engine trouble.
– Monitor fuel economy: A sudden drop may indicate a sensor or emissions issue.
When to See a Mechanic
While many check engine light issues can be handled at home, some require professional help. See a mechanic if:
– The light is flashing (indicates a severe misfire that can damage the catalytic converter)
– You smell fuel or see smoke
– The car is running poorly, stalling, or losing power
– You’re unable to read or interpret the trouble codes
– The light keeps coming back after multiple resets
A flashing check engine light is a red flag. Drive to a repair shop immediately—don’t wait.
Final Thoughts
Resetting the check engine light on your 2015 Honda Accord doesn’t have to be intimidating. With the right tools and knowledge, you can do it safely and effectively. The key is to always diagnose the problem first. Whether you use an OBD2 scanner, disconnect the battery, or rely on a drive cycle, make sure the underlying issue is fixed.
Remember: the check engine light is your car’s way of saying, “Hey, something’s not right.” Ignoring it can lead to bigger problems down the road. But with this guide, you’re equipped to handle it like a pro.
Take action today. Scan those codes, fix the issue, and enjoy the peace of mind that comes with a healthy engine.