How to Check Engine Light 2016 Chrysler 300

This guide shows you how to check engine light 2016 Chrysler 300 safely and accurately. You’ll learn to read error codes, reset the light, and decide when to see a mechanic.

Key Takeaways

• Understand the Check Engine Light: It’s not just a warning—it’s a diagnostic tool that alerts you to engine or emissions issues in your 2016 Chrysler 300.
• Use an OBD2 Scanner: A simple plug-and-play device reads trouble codes and helps identify the root cause of the light.
• Check Gas Cap First: A loose or damaged gas cap is a common, easy fix that can trigger the light.
• Don’t Ignore the Light: Even if the car runs fine, unresolved issues can lead to costly repairs or reduced fuel efficiency.
• Reset the Light Properly: After fixing the issue, use the scanner or disconnect the battery to clear the code—don’t just cover it up.
• Know When to Call a Pro: Complex issues like catalytic converter or sensor failures need expert diagnosis and repair.
• Stay Updated in 2026: Modern tools and apps make diagnosing your Chrysler 300 easier than ever—use them to your advantage.

How to Check Engine Light 2016 Chrysler 300: A Complete 2026 Guide

If you’re driving a 2016 Chrysler 300 and the dreaded check engine light pops up on your dashboard, don’t panic. While it can be alarming, this light is actually your car’s way of saying, “Hey, something needs attention.” The good news? In 2026, diagnosing and addressing the issue is easier than ever—thanks to affordable tools, smartphone apps, and a wealth of online resources.

This guide will walk you through how to check engine light 2016 Chrysler 300 step by step. Whether you’re a DIY enthusiast or just want to understand what’s going on under the hood, you’ll learn how to read error codes, perform basic checks, and decide whether you can fix it yourself or need a mechanic. By the end, you’ll feel confident handling this common automotive concern.

What Does the Check Engine Light Mean?

The check engine light—also known as the malfunction indicator lamp (MIL)—is part of your car’s onboard diagnostics system (OBD2). When it illuminates, it means the car’s computer has detected a problem with the engine, transmission, or emissions system.

In your 2016 Chrysler 300, this light can appear in two ways:
– Steady (solid) light: Indicates a minor issue, like a loose gas cap or a faulty oxygen sensor.
– Flashing light: Signals a serious problem, such as engine misfire, that could damage the catalytic converter if ignored.

Don’t assume the light is a false alarm. Even if your car seems to run fine, underlying issues can reduce performance, lower fuel economy, or lead to bigger repairs down the road.

Why the Check Engine Light Comes On in a 2016 Chrysler 300

The 2016 Chrysler 300 is a reliable sedan, but like any vehicle, it can develop issues over time. Common reasons for the check engine light include:

• Loose or damaged gas cap: This is the #1 cause. A missing or cracked cap allows fuel vapors to escape, triggering the light.
• Faulty oxygen (O2) sensor: These sensors monitor exhaust gases. A bad one can hurt fuel efficiency and emissions.
• Mass airflow (MAF) sensor issues: This sensor measures incoming air. Dirt or failure can cause rough idling or poor acceleration.
• Catalytic converter problems: Often a result of ignored misfires or bad spark plugs.
• Spark plug or ignition coil failure: Leads to engine misfires and reduced power.
• Evaporative emissions (EVAP) system leaks: Small leaks in the fuel vapor system can trigger the light.

Knowing these common causes helps you focus your troubleshooting efforts.

Tools You’ll Need to Check the Engine Light

Before diving in, gather these tools. Most are affordable and reusable:

• OBD2 scanner: A handheld device that plugs into your car’s diagnostic port. Prices range from $20 to $100. Look for Bluetooth models that work with smartphone apps.
• Smartphone with OBD2 app: Apps like Torque Pro (Android) or OBD Fusion (iOS) turn your phone into a diagnostic tool when paired with a Bluetooth scanner.
• Flashlight: Helps you see under the hood and around the gas cap area.
• Gloves and safety glasses: Basic safety gear, especially if you’re checking components.
• Owner’s manual: Your 2016 Chrysler 300 manual has useful info on dashboard lights and maintenance.

You don’t need to be a mechanic to use these tools. Most OBD2 scanners are plug-and-play—just connect and follow the prompts.

Step 1: Don’t Panic—Assess the Situation

When the check engine light comes on, stay calm. Here’s what to do first:

Check if the Light is Steady or Flashing

– If it’s steady, you likely have time to diagnose and fix the issue.
– If it’s flashing, pull over safely and turn off the engine. A flashing light means active misfires that can damage the catalytic converter. Have the car towed if necessary.

Note Any Changes in Driving

Ask yourself:
– Is the engine running rough or hesitating?
– Is there a loss of power or poor fuel economy?
– Do you smell gas or see smoke?

These clues help narrow down the problem.

Check the Gas Cap

This is the easiest fix and often the culprit:
1. Turn off the engine.
2. Open the fuel door and unscrew the gas cap.
3. Inspect it for cracks, wear, or damage.
4. Tighten it firmly until you hear it click 3–4 times.
5. Drive for 50–100 miles. The light may turn off on its own if the cap was loose.

If the light stays on, move to the next step.

Step 2: Locate the OBD2 Port

The OBD2 port is where you’ll plug in your scanner. In the 2016 Chrysler 300, it’s located under the dashboard on the driver’s side.

How to Find It

1. Sit in the driver’s seat.
2. Look under the steering column, near the knee area.
3. You’ll see a rectangular port (about 1.5 inches wide) with 16 pins.

It’s usually uncovered, but sometimes tucked behind a small panel. No tools needed—just reach in and feel for it.

Tip:

If you can’t find it, check your owner’s manual or search “2016 Chrysler 300 OBD2 port location” online. Most models have it in the same spot.

Step 3: Use an OBD2 Scanner to Read the Code

Now it’s time to get answers. The scanner will read the trouble code stored in your car’s computer.

How to Use the Scanner

1. Turn the ignition to the “ON” position (but don’t start the engine).
2. Plug the OBD2 scanner into the port.
3. Turn on the scanner. It should power up automatically.
4. Follow the on-screen prompts to “Read Codes” or “Scan.”
5. The scanner will display a code, such as P0455 or P0171.

Understanding the Code

OBD2 codes follow a standard format:
– First character: System (P = Powertrain, B = Body, C = Chassis, U = Network)
– Next digit: 0 = Generic (standard), 1 = Manufacturer-specific
– Last three digits: Specific issue

For example:
– P0455: Large EVAP leak (often the gas cap)
– P0171: System too lean (air/fuel mixture issue)
– P0300: Random/multiple cylinder misfire

Using a Smartphone App

If you have a Bluetooth OBD2 scanner:
1. Pair it with your phone via Bluetooth.
2. Open the app (e.g., Torque Pro).
3. Tap “Connect” and wait for the link.
4. Select “Read Fault Codes” or “DTCs.”
5. The app will show the code and often a plain-English description.

This method is user-friendly and lets you save logs for future reference.

Step 4: Research the Code

Once you have the code, it’s time to understand what it means.

Use Reliable Sources

Don’t rely on random forum posts. Use trusted sites like:
– OBD-Codes.com
– Chrysler’s official service site
– YouTube tutorials for 2016 Chrysler 300

Search for your specific code + “2016 Chrysler 300” to get model-specific advice.

Example: P0420 – Catalyst System Efficiency Below Threshold

This code often means the catalytic converter isn’t working well. But before replacing it (which costs $1,000+), check:
– Oxygen sensors (upstream and downstream)
– Exhaust leaks
– Engine misfires

A bad O2 sensor can mimic a bad catalytic converter.

Tip:

Some codes have multiple causes. Always research before buying parts.

Step 5: Perform Basic Checks and Fixes

Based on the code, you may be able to fix the issue yourself.

Fix 1: Tighten or Replace the Gas Cap

If the code points to an EVAP leak (like P0455):
1. Remove the gas cap.
2. Inspect the seal—look for cracks or brittleness.
3. Replace it if damaged. OEM caps are best, but quality aftermarket ones work too.
4. Tighten it securely.
5. Drive for a few days. The light should reset.

Fix 2: Clean the Mass Airflow (MAF) Sensor

If you have a P0171 or rough idle:
1. Locate the MAF sensor (between the air filter and throttle body).
2. Unplug the electrical connector.
3. Remove the sensor (usually held by two screws).
4. Spray it with MAF cleaner (not carb cleaner!).
5. Let it dry completely.
6. Reinstall and reconnect.

This often resolves lean codes.

Fix 3: Replace Spark Plugs or Ignition Coils

For misfire codes (P0300–P0308):
1. Check spark plug condition. In a 2016 Chrysler 300, they should be replaced every 60,000–100,000 miles.
2. If one cylinder is misfiring, swap its ignition coil with another to see if the code follows.
3. Replace faulty coils or plugs as needed.

Use a torque wrench to avoid over-tightening.

When to Skip DIY

If the code involves:
– Transmission issues
– Internal engine problems
– Advanced electronics

It’s best to consult a professional.

Step 6: Clear the Check Engine Light

After fixing the issue, you’ll want to turn off the light.

Method 1: Use the OBD2 Scanner

1. With the scanner connected, select “Clear Codes” or “Erase DTCs.”
2. Confirm the action.
3. The light should go off immediately.

Method 2: Disconnect the Battery

If you don’t have a scanner:
1. Turn off the engine and remove the key.
2. Disconnect the negative battery terminal.
3. Wait 15–30 minutes (this resets the computer).
4. Reconnect the terminal.
5. Start the car. The light should be off.

Note: This method may reset radio presets and climate settings.

Method 3: Drive Cycle Reset

Some issues require a “drive cycle” to reset:
1. Drive under various conditions (city, highway, cold start).
2. The car’s computer will retest systems.
3. If no problems are found, the light turns off.

This can take 50–100 miles.

Step 7: Monitor and Prevent Future Issues

Once the light is off, stay proactive.

Regular Maintenance

– Change oil every 5,000–7,500 miles.
– Replace air filter every 15,000–30,000 miles.
– Inspect spark plugs and coils at 60,000 miles.
– Use quality fuel and additives occasionally.

Use a Bluetooth Scanner Regularly

In 2026, many drivers keep a Bluetooth OBD2 scanner in their glove box. Use it monthly to:
– Check for pending codes (early warnings)
– Monitor fuel trims and sensor data
– Track engine performance

Apps can even send alerts if something goes wrong.

Keep Records

Save scan logs and repair receipts. This helps with resale value and warranty claims.

Troubleshooting Common Problems

Even with the right tools, you might run into issues.

Scanner Won’t Connect

– Make sure the ignition is ON.
– Check the OBD2 port for dirt or damage.
– Try a different scanner or app.
– Restart the car and scanner.

Light Comes Back On

This means the problem wasn’t fully fixed. Re-scan and check for:
– Intermittent faults
– Loose connections
– New codes

Multiple Codes Appear

Start with the most critical (e.g., misfires) and work down. Some codes are side effects of a primary issue.

No Code, But Light is On

Rare, but possible. Could indicate a software glitch or sensor communication error. Try a battery reset or visit a dealer.

When to See a Mechanic

DIY is great, but know your limits. See a professional if:
– The light is flashing.
– You have transmission or drivetrain codes.
– The issue involves internal engine work.
– You’re unsure about electrical systems.
– The problem persists after repairs.

In 2026, many mechanics use advanced diagnostic tools that go beyond basic OBD2 scans. They can perform live data analysis, smoke tests for leaks, and software updates.

Conclusion

Checking the engine light on your 2016 Chrysler 300 doesn’t have to be stressful. With the right tools and knowledge, you can diagnose common issues, perform simple fixes, and keep your car running smoothly. Remember: the light is a warning, not a death sentence. Address it early, stay informed, and use modern tools to your advantage.

By following this guide, you’ve learned how to check engine light 2016 Chrysler 300 like a pro. Whether it’s a loose gas cap or a faulty sensor, you now have the confidence to take action. Stay safe, stay informed, and enjoy the ride.