Discover how to reset the check engine light on your Infiniti G35 using simple methods like the OBD2 scanner, battery disconnect, or manual reset. This guide covers everything from diagnosis to prevention to keep your car running smoothly.
Key Takeaways
- Understand the cause first: Never reset the check engine light without diagnosing the underlying issue—otherwise, it will likely return.
- Use an OBD2 scanner for accuracy: This is the most reliable and recommended method to clear the light and read error codes.
- Battery disconnect is a temporary fix: While it may reset the light, it also erases ECU memory and may not work on newer G35 models.
- Manual reset methods vary by model year: Some older G35s allow a pedal-based reset, but this doesn’t work on all trims or years.
- Resetting doesn’t fix the problem: The light will come back if the issue isn’t repaired—address the root cause first.
- Clear codes after repairs: Always reset the light after fixing the problem to confirm the repair was successful.
- Prevent future issues: Regular maintenance like oil changes, air filter replacements, and spark plug checks can help avoid check engine light triggers.
How to Reset G35 Check Engine Light: A Complete Step-by-Step Guide
If you’re driving an Infiniti G35 and the dreaded check engine light has popped up on your dashboard, don’t panic—you’re not alone. This warning light can appear for dozens of reasons, from a loose gas cap to a faulty oxygen sensor. But once you’ve diagnosed and fixed the issue, the next step is resetting the light so your dashboard stays clean and your car’s computer knows everything is back to normal.
In this comprehensive guide, you’ll learn how to reset the G35 check engine light using multiple proven methods, including using an OBD2 scanner, disconnecting the battery, and even a manual pedal reset (where applicable). We’ll also walk you through how to diagnose the problem first, because resetting the light without fixing the root cause is just a temporary band-aid.
Whether you’re a DIY enthusiast or a first-time car owner, this guide is written in simple, easy-to-follow language. No mechanic jargon, no confusing diagrams—just clear steps to get your G35 back to peak performance.
By the end of this guide, you’ll know exactly what to do when that check engine light appears, how to safely reset it, and how to prevent it from coming back. Let’s get started.
Why the Check Engine Light Comes On in Your G35
Visual guide about How to Reset G35 Check Engine Light
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Before we dive into resetting the light, it’s important to understand why it turned on in the first place. The check engine light—also known as the Malfunction Indicator Lamp (MIL)—is part of your car’s onboard diagnostics system (OBD2). When the Engine Control Unit (ECU) detects a problem with the engine, emissions, or related systems, it triggers the light and stores a diagnostic trouble code (DTC).
Common reasons the check engine light comes on in a G35 include:
- A loose or damaged gas cap
- Faulty oxygen (O2) sensor
- Mass airflow (MAF) sensor issues
- Spark plug or ignition coil problems
- Catalytic converter inefficiency
- Evaporative emissions system leaks
- Exhaust gas recirculation (EGR) valve malfunction
Ignoring the light can lead to reduced fuel efficiency, increased emissions, and even engine damage over time. That’s why it’s crucial to diagnose the issue first before attempting to reset the light.
Step 1: Diagnose the Problem Before Resetting
You should never reset the check engine light without knowing what caused it. Resetting it without fixing the problem is like turning off a fire alarm while the house is still on fire—it doesn’t solve anything.
Use an OBD2 Scanner to Read the Code
The best way to diagnose the issue is by using an OBD2 scanner. These devices plug into your car’s OBD2 port (usually located under the dashboard, near the driver’s knees) and read the trouble codes stored in the ECU.
Here’s how to do it:
- Turn off the engine and locate the OBD2 port. In most G35 models (2003–2007), it’s under the dashboard on the driver’s side, near the steering column.
- Plug the OBD2 scanner into the port. Make sure it’s securely connected.
- Turn the ignition to the “ON” position (but don’t start the engine).
- Follow the scanner’s instructions to read the codes. Most scanners will display a code like P0420 or P0171.
- Write down the code and look it up online or in the scanner’s manual to understand what it means.
For example:
- P0420 = Catalyst system efficiency below threshold (likely a bad catalytic converter)
- P0171 = System too lean (bank 1)—could be a vacuum leak or MAF sensor issue
- P0455 = Large evaporative emission leak—often a loose gas cap
Once you know the code, you can research the fix or take your car to a mechanic if needed.
Check the Gas Cap (Quick Fix!)
One of the most common—and easiest—causes of the check engine light is a loose or damaged gas cap. If you recently filled up your gas tank and the light came on, this could be the culprit.
To check:
- Turn off the engine and locate the gas cap.
- Unscrew it and inspect the rubber seal for cracks or wear.
- Reinstall it tightly—turn it until you hear it click 3–5 times.
- Drive the car for a few days. If the light was due to a loose cap, it may turn off on its own after a few drive cycles.
If the light stays off, great! No reset needed. But if it comes back, you’ll need to dig deeper.
Step 2: Fix the Underlying Issue
Now that you’ve identified the problem, it’s time to fix it. Depending on the code, this could be as simple as replacing the gas cap or as complex as replacing the catalytic converter.
Here are some common fixes for G35 check engine light issues:
Replace the Gas Cap
If the code points to an evaporative emissions leak (like P0455), a new gas cap might solve the problem. OEM (original equipment manufacturer) caps are recommended for best performance.
Clean or Replace the MAF Sensor
A dirty mass airflow sensor can cause lean codes (P0171/P0174). Use MAF cleaner spray to clean it, or replace it if it’s damaged.
Replace Spark Plugs and Ignition Coils
Misfire codes (like P0300–P0306) often stem from worn spark plugs or failing ignition coils. The G35 uses coil-on-plug ignition, so each cylinder has its own coil. Replace them as a set for best results.
Replace the Oxygen Sensor
O2 sensor codes (like P0135 or P0141) usually mean the sensor is faulty. The G35 has multiple O2 sensors—front and rear. Replace the one indicated by the code.
Address Catalytic Converter Issues
A P0420 code often means the catalytic converter is no longer efficient. This is a more expensive repair, but driving with a failed cat can damage the engine and increase emissions.
Once the repair is complete, you’re ready to reset the check engine light.
Step 3: How to Reset the G35 Check Engine Light
Now that the problem is fixed, it’s time to clear the trouble codes and turn off the light. There are several ways to do this, but some are more reliable than others.
Method 1: Use an OBD2 Scanner (Recommended)
This is the most accurate and recommended method to reset the check engine light on your G35.
Steps:
- Plug the OBD2 scanner into the OBD2 port (same as when you read the code).
- Turn the ignition to the “ON” position (engine off).
- Navigate the scanner menu to find the “Clear Codes” or “Erase Codes” option.
- Confirm the action. The scanner will send a command to the ECU to delete all stored trouble codes.
- Turn off the ignition and unplug the scanner.
- Start the engine. The check engine light should be off.
Pro Tip: After clearing the codes, drive the car for 20–30 minutes under normal conditions (city and highway driving). This allows the ECU to run its self-tests and confirm the repair was successful. If the light stays off, you’re good to go.
Method 2: Disconnect the Battery (Temporary Fix)
Some people reset the check engine light by disconnecting the car battery. This method works by cutting power to the ECU, which resets its memory—including stored trouble codes.
However, this method has drawbacks:
- It may not work on newer G35 models (2005–2007) with advanced ECU systems.
- It resets other systems too—radio presets, clock, seat memory, and adaptive transmission settings may be lost.
- The light may come back if the problem wasn’t fixed.
If you still want to try it, here’s how:
- Turn off the engine and remove the key.
- Open the hood and locate the battery.
- Use a wrench to loosen the negative (-) terminal clamp.
- Disconnect the negative cable and wait at least 15 minutes. This ensures the ECU fully resets.
- Reconnect the cable and tighten it securely.
- Start the engine. The check engine light should be off—for now.
Note: After reconnecting the battery, you may need to reset the radio, clock, and power windows. Also, the car may run rough for a few minutes as the ECU relearns driving patterns.
Method 3: Manual Reset (Pedal Method – Limited Use)
Some older G35 models (mainly 2003–2004) allow a manual reset using the accelerator pedal. This method tricks the ECU into thinking the car has completed a drive cycle, which can clear pending codes.
However, this method:
- Does not work on all G35 trims or model years.
- Only clears pending codes—not confirmed ones.
- Is not guaranteed to turn off the check engine light.
If you want to try it, follow these steps:
- Turn the ignition to “ON” (engine off).
- Press the accelerator pedal all the way down and hold it for 3 seconds.
- Release the pedal.
- Press and hold the pedal again for 3 seconds.
- Repeat this press-hold-release cycle two more times (3 times total).
- Turn the ignition off.
- Wait 10 seconds, then start the engine.
If the light is off, great. But don’t rely on this method for confirmed trouble codes.
Troubleshooting: What If the Light Comes Back?
Even after resetting the light, it may return. This usually means one of two things:
The Problem Wasn’t Fully Fixed
For example, if you cleared a P0420 code but didn’t replace the catalytic converter, the ECU will detect the same inefficiency and turn the light back on.
Solution: Recheck the repair. Make sure all parts were installed correctly and that no related components (like O2 sensors) are faulty.
The ECU Needs More Drive Cycles
After a reset, the ECU runs a series of self-tests called “drive cycles.” If the light comes back after a few days, it may mean the system hasn’t completed all tests yet.
Solution: Drive the car normally for 50–100 miles, including highway speeds. This allows the ECU to monitor emissions and engine performance. If the light stays off after this, the issue is likely resolved.
Intermittent Issues
Some problems, like a loose wire or a failing sensor, only occur under certain conditions (e.g., cold weather or high RPM). These can cause the light to come and go.
Solution: Use a scanner to check for “pending” codes. These are codes that haven’t yet triggered the light but indicate a developing issue.
Preventing Future Check Engine Light Issues
The best way to avoid dealing with the check engine light is to prevent it from coming on in the first place. Regular maintenance is key.
Here are some tips to keep your G35 running smoothly:
Follow the Maintenance Schedule
Refer to your owner’s manual for the recommended service intervals. Key items include:
- Oil and filter changes every 5,000–7,500 miles
- Air filter replacement every 15,000–30,000 miles
- Spark plug replacement every 60,000–100,000 miles (depending on type)
- Fuel system cleaning every 30,000 miles
Use Quality Fuel and Additives
Fill up at reputable gas stations and consider using a fuel injector cleaner every 3,000–5,000 miles to keep the fuel system clean.
Inspect the Gas Cap Regularly
Check the gas cap for cracks or wear every few months. Replace it if needed—it’s a cheap part that can prevent big problems.
Watch for Early Warning Signs
Pay attention to changes in engine performance, fuel economy, or exhaust smell. These can be early signs of a problem before the check engine light comes on.
Conclusion
Resetting the check engine light on your Infiniti G35 doesn’t have to be intimidating. By following this guide, you now know how to diagnose the issue, fix it properly, and safely reset the light using the best methods available.
Remember: Always diagnose the problem first. Resetting the light without fixing the cause is a waste of time—and could lead to bigger issues down the road.
The OBD2 scanner method is the most reliable and recommended approach. It’s accurate, safe, and doesn’t disrupt other systems in your car. While disconnecting the battery or using the pedal method might work in some cases, they come with limitations and risks.
Once the light is off, drive your G35 normally to allow the ECU to complete its self-tests. If the light stays off, congratulations—you’ve successfully resolved the issue.
And don’t forget prevention. Regular maintenance, quality fuel, and attention to small details can go a long way in keeping that check engine light from ever coming on again.
With the knowledge from this guide, you’re now equipped to handle the check engine light like a pro. Your G35 will thank you with better performance, improved fuel economy, and fewer trips to the mechanic.