Reset the check engine light on your 2026 Chrysler 300 quickly and safely using the OBD2 scanner method—no dealership visit required. Locate the OBD2 port under the dashboard, plug in a compatible scanner, and follow the prompts to clear the code after verifying the issue is resolved. Always address underlying problems first to avoid triggering the light again.

How to Reset Check Engine Light on Chrysler 300 in 2026

Key Takeaways

• Diagnose first: Use an OBD2 scanner to identify the issue before resetting.
• Turn ignition on: Switch to “ON” position without starting the engine.
• Press gas pedal: Fully depress it three times within 10 seconds.
• Wait for reset: Observe dashboard lights cycling to confirm reset success.
• Clear codes: Use OBD2 scanner to erase stored trouble codes.
• Verify fix: Drive 50-100 miles to ensure light stays off.

Why This Matters / Understanding the Problem

The check engine light on your Chrysler 300 isn’t just a nagging orange symbol on your dashboard—it’s your car’s way of saying, “Hey, something’s not right.” In 2026, newer Chrysler 300 models come with advanced onboard diagnostics (OBD-II), making it easier than ever to identify and fix issues. But when you’ve resolved the problem, that light might still stay on, causing unnecessary stress and even failing emissions tests.

If you’re wondering how to reset check engine light on Chrysler 300 in 2026, you’re not alone. Many drivers assume the light will turn off automatically after repairs, but that’s not always the case. The light only resets after the car’s computer verifies the problem is fixed—and sometimes, you need to help it along. Whether you’ve replaced a faulty oxygen sensor or tightened the gas cap, resetting the light ensures your vehicle’s systems are communicating properly and gives you peace of mind.

Ignoring the light or trying quick fixes without diagnosing the root cause can lead to bigger, more expensive problems. That’s why learning how to reset check engine light on Chrysler 300 in 2026 the right way is essential. It’s not just about turning off a light—it’s about maintaining your car’s health, safety, and performance.

What You Need

Before you start, gather the right tools. You don’t need to be a mechanic, but having the basics makes the process smooth and safe. Here’s what you’ll need to reset the check engine light on your 2026 Chrysler 300:

• OBD-II code reader or scanner – This is the most reliable tool for reading and clearing trouble codes. Even a basic $20–$50 Bluetooth scanner (like the BAFX or Autel) works well. For advanced diagnostics, consider a full-featured scanner with live data.
• Smartphone (optional) – If you use a Bluetooth scanner, you’ll need a phone to run the companion app (e.g., Torque Pro, Car Scanner ELM OBD2).
• Owner’s manual – Helps you locate the OBD-II port and understand your specific model’s quirks.
• Pen and paper or notes app – To record the diagnostic trouble codes (DTCs) before clearing them. This helps if the light comes back.
• Fully charged car battery – A weak battery can cause false codes or prevent the system from resetting properly.
• Time and a safe workspace – Park on a flat surface, turn off the engine, and set the parking brake. You’ll need about 10–20 minutes.

Pro Tip: If you’ve already fixed the issue (like replacing a spark plug or fixing a vacuum leak), make sure the repair was successful and the car has been driven for at least 10–20 miles. The system needs time to run self-tests before it’s ready to reset.

Step-by-Step Guide to How to Reset Check Engine Light on Chrysler 300 in 2026

Follow these simple, clear steps to reset the check engine light on your 2026 Chrysler 300. Whether you’re using a handheld scanner or a smartphone app, the process is straightforward—once you know where to start.

Step 1: Park Safely and Turn Off the Engine

Start by parking your Chrysler 300 on a level surface. Turn off the engine, remove the key (or press the start button if it’s a push-to-start model), and set the parking brake. This ensures safety and prevents the car from moving while you’re working.

Wait about 30 seconds after turning off the engine. This allows the vehicle’s computer to fully shut down and reset its temporary memory. It’s a small step, but it helps prevent glitches during the scan.

Warning: Never work on the car while the engine is running or the ignition is in the “ON” position unless specifically instructed by the scanner app. Doing so can damage sensors or trigger new error codes.

Step 2: Locate the OBD-II Port

In the 2026 Chrysler 300, the OBD-II port is typically located under the driver’s side dashboard, near the steering column. It’s a 16-pin connector, usually covered by a small plastic flap. If you can’t find it, check your owner’s manual—Chrysler often places it within easy reach, just above the gas pedal or slightly to the left.

Open the flap and inspect the port. Make sure it’s clean and free of dust or debris. A dirty connection can cause communication errors with the scanner. Use a dry cloth to wipe it gently if needed.

This step is crucial because without a solid connection, your scanner won’t be able to read the codes—or worse, it might misinterpret them. Think of it like plugging in a USB cable: if it’s loose, nothing works.

Step 3: Plug In the OBD-II Scanner

Take your OBD-II scanner and plug it into the port. Make sure it clicks in securely—don’t force it, but ensure it’s seated fully. The scanner will usually power on automatically when connected.

If you’re using a Bluetooth scanner, turn on your smartphone’s Bluetooth and open the app. Pair the scanner with your phone (the pairing code is usually “1234” or “0000”). Most apps will guide you through this process.

For handheld scanners, you’ll see a menu screen. Select “Read Codes” or “DTCs” to start the scan. The scanner will communicate with your car’s ECU (engine control unit) and pull up any stored trouble codes.

Pro Tip: Write down the codes (like P0171 or P0420) before clearing them. If the light returns, you’ll know which system needs attention. This is especially helpful if you’re troubleshooting recurring issues.

Step 4: Read and Understand the Trouble Codes

The scanner will display a list of diagnostic trouble codes (DTCs). These codes tell you exactly what’s wrong. For example:

• P0171 – System Too Lean (Bank 1)
• P0457 – Evaporative Emission System Leak (likely a loose gas cap)
• P0300 – Random/Multiple Cylinder Misfire Detected

Use the scanner’s built-in code definitions or search online (e.g., “P0457 Chrysler 300 meaning”) to understand what each code means. This step is essential—don’t skip it. If you clear the code without fixing the root cause, the light will come back, and you could be wasting time and money.

For example, if the code is P0457, check your gas cap. It might just need to be tightened or replaced. But if it’s P0300, you might need to replace spark plugs or ignition coils. Knowing the code helps you fix the real problem, not just the symptom.

Step 5: Fix the Underlying Issue (If Not Already Done)

Before you reset the check engine light, make sure the issue has been resolved. This is the most important part of the process. Resetting a code without fixing the problem is like putting a band-aid on a broken leg.

Here are common fixes based on codes:

• Loose gas cap – Tighten it until it clicks 3–4 times. Replace if cracked or damaged.
• O2 sensor failure – Replace the sensor (usually located near the catalytic converter).
• Spark plug or ignition coil issue – Replace faulty components. Use OEM parts for best results.
• EVAP system leak – Inspect hoses, canister, and purge valve. A mechanic may be needed for complex leaks.

After repairs, drive the car for at least 10–20 miles. This gives the ECU time to run self-diagnostic tests and confirm the issue is resolved. Some systems (like the EVAP) need multiple drive cycles to complete tests.

Warning: Never reset the light immediately after a repair and expect it to stay off. The car’s computer needs time to verify the fix. If you clear the code too soon, the light may return within a few miles.

Step 6: Clear the Check Engine Light

Once you’re confident the issue is fixed, it’s time to reset the check engine light. On your scanner, select “Clear Codes” or “Erase DTCs.” Confirm the action when prompted.

For Bluetooth apps, tap “Clear Codes” or “Reset MIL” (Malfunction Indicator Lamp). The scanner will send a command to the ECU to erase all stored trouble codes and turn off the check engine light.

You should see the light go off within a few seconds. If it doesn’t, double-check your connection and try again. If the light stays on, the car may still detect an issue or need more drive cycles to complete tests.

This is the moment you’ve been waiting for—the light is off, and your Chrysler 300 is back to normal. But don’t unplug the scanner just yet.

Step 7: Perform a System Re-Test (Optional but Recommended)

After clearing the codes, use the scanner to run a “System Status” or “Readiness Monitors” check. This tells you whether your car’s emissions systems have completed their self-tests.

In the 2026 Chrysler 300, key monitors include:

• O2 Sensor Monitor
• Catalyst Monitor
• EVAP System Monitor
• O2 Heater Monitor

If any monitor shows “Not Ready,” drive the car for another 20–50 miles, following a mix of city and highway conditions. This helps complete the tests. Once all monitors are “Ready,” your car is fully reset and ready for emissions testing (if required).

Step 8: Unplug the Scanner and Verify

Unplug the OBD-II scanner and close the port cover. Start your Chrysler 300 and check the dashboard. The check engine light should remain off.

Drive for 10–15 minutes to ensure the light doesn’t come back. If it does, note the new code and repeat the process. A returning light means the issue wasn’t fully resolved.

You’ve now successfully learned how to reset check engine light on Chrysler 300 in 2026—the right way. No guesswork, no shortcuts.

Pro Tips & Common Mistakes to Avoid

Even with a clear guide, small mistakes can lead to big headaches. Here are expert tips and pitfalls to avoid when resetting your check engine light.

Pro Tip 1: Don’t Skip the Drive Cycle

After repairs, your car needs time to run diagnostic tests. These “drive cycles” involve specific conditions: cold start, acceleration, steady speed, deceleration, and idle. Without them, monitors won’t complete, and the light may stay on.

For example, to complete the EVAP monitor, you might need to:

• Start the car cold (after sitting 8+ hours)
• Drive 5–10 minutes at 30–40 mph
• Accelerate to 55 mph and cruise for 5 minutes
• Decelerate and stop for 2 minutes

Follow your scanner’s “Drive Cycle Guide” if available.

Pro Tip 2: Use a Quality Scanner

Not all scanners are equal. Cheap models may not read all codes or support Chrysler-specific functions. Invest in a reliable OBD-II scanner with Chrysler 300 compatibility. Look for models that support:

• Live data streaming
• Freeze frame data
• Readiness monitors
• Enhanced DTCs (for Chrysler-specific codes)

Pro Tip 3: Check the Battery Voltage

A weak battery (below 12.4 volts) can cause false codes or prevent the system from resetting. Use a multimeter to check your battery voltage before scanning. If it’s low, charge it or replace it.

Warning: Never disconnect the battery to reset the check engine light. This erases all learned data (like fuel trim), forces the car to re-learn idle settings, and may trigger new codes. It’s an outdated method that does more harm than good.

Common Mistake 1: Clearing Codes Without Diagnosis

Some drivers plug in a scanner and hit “Clear Codes” without reading them. This is dangerous. You’re essentially telling the car, “Everything’s fine,” when it’s not. The light will likely return, and you’ll waste time and money.

Always read the code first. Even if you can’t fix it yourself, knowing the code helps a mechanic diagnose the issue faster.

Common Mistake 2: Ignoring Recurring Codes

If the check engine light comes back with the same code, the issue wasn’t fixed. For example, if P0301 (Cylinder 1 Misfire) returns, don’t just clear it again. Investigate further—could be a bad fuel injector, vacuum leak, or wiring issue.

Common Mistake 3: Using the Wrong OBD-II Protocol

The 2026 Chrysler 300 uses CAN (Controller Area Network) protocol. Most modern scanners support this, but older models may not. If your scanner can’t connect, check its compatibility list or upgrade to a CAN-compatible model.

FAQs About How to Reset Check Engine Light on Chrysler 300 in 2026

Here are the most common questions drivers ask—answered clearly and honestly.

Q1: Can I reset the check engine light without a scanner?

Technically, yes, but it’s not recommended. Some people try disconnecting the battery for 10–15 minutes, but this resets all electronic systems (radio, clock, seat memory, etc.) and can trigger new codes. The only reliable method is using an OBD-II scanner. It’s faster, safer, and more precise.

Q2: How long does it take for the check engine light to reset after a repair?

It depends. After a repair, the light may go off immediately if the system detects the fix. But often, you need to drive 20–50 miles over 1–3 days to complete all readiness monitors. Use your scanner to check “Readiness Status” for a clear answer.

Q3: Will the check engine light turn off by itself?

Sometimes. If the issue was temporary (like a loose gas cap), the light may turn off after a few drive cycles. But if the problem persists or is serious (e.g., catalytic converter failure), the light will stay on until you fix it and reset it manually.

Q4: Is it safe to drive with the check engine light on?

If the light is solid (not flashing), you can drive short distances. But get it checked soon. A flashing light means severe misfire—pull over immediately. Ignoring it can damage the catalytic converter and cost thousands in repairs.

Q5: Can I pass emissions with the check engine light on?

No. In most states, a lit check engine light automatically fails emissions tests. Even if the car runs fine, the light indicates a potential emissions issue. Reset the light and ensure all monitors are “Ready” before testing.

Q6: What if the light comes back after resetting?

Read the new code immediately. If it’s the same as before, the repair didn’t work. If it’s a new code, a different issue has developed. Use your scanner to get details and address it promptly.

Q7: Are OBD-II scanners expensive?

Not anymore. Basic models start at $20, while advanced scanners with live data and Chrysler-specific functions cost $80–$150. For occasional use, a budget scanner works fine. For DIYers, a mid-range model is worth the investment.

Final Thoughts

Learning how to reset check engine light on Chrysler 300 in 2026 is one of the most valuable skills you can have as a car owner. It saves time, money, and stress—and keeps your vehicle running safely and efficiently.

Remember: the goal isn’t just to turn off the light. It’s to understand what caused it, fix the problem, and ensure it stays off. Use an OBD-II scanner, follow the steps carefully, and never skip the diagnosis phase.

Keep your scanner in the glove box, along with a small notebook for recording codes. That way, you’ll be ready whenever the light pops up—whether it’s a simple gas cap or a deeper engine issue.

And if you’re ever unsure, don’t hesitate to consult a trusted mechanic. Some problems are best left to the pros. But for everyday fixes, you’ve now got the tools and knowledge to handle it yourself.

Your Chrysler 300 is more than just a car—it’s a machine designed for performance and reliability. By taking the time to reset the check engine light properly, you’re giving it the care it deserves.

So go ahead, plug in that scanner, and take control. The road ahead is clearer when you know what’s under the hood.