This guide walks you through how to check the engine light on a 2016 Chrysler 300, including reading error codes, understanding common causes, and deciding when to seek professional help. Whether you’re a DIY enthusiast or just want to stay informed, you’ll gain the knowledge to respond confidently when that warning light appears.
Key Takeaways
- Understand what the check engine light means: It signals a problem with your vehicle’s engine, emissions, or onboard systems—don’t ignore it.
- Use an OBD2 scanner to read error codes: This tool connects to your car’s diagnostic port and reveals specific issues behind the warning light.
- Locate the OBD2 port in your 2016 300: It’s typically under the dashboard on the driver’s side, near the steering column.
- Interpret common trouble codes: Codes like P0420 or P0300 point to catalytic converter or misfire issues—knowing them helps prioritize repairs.
- Reset the light after repairs: Once the issue is fixed, use your scanner or disconnect the battery to clear the code and turn off the light.
- Know when to visit a mechanic: If the light flashes or returns after resetting, professional diagnosis is essential.
- Prevent future issues: Regular maintenance like oil changes and spark plug replacements can reduce check engine light triggers.
Introduction: Why the Check Engine Light Matters
The check engine light—also known as the malfunction indicator lamp (MIL)—is one of the most important warning signals in your 2016 Chrysler 300. When it illuminates, it’s your car’s way of saying, “Hey, something’s not right.” Ignoring it could lead to reduced fuel efficiency, increased emissions, or even serious engine damage over time.
In this guide, we’ll walk you through how to check the engine light on a 2016 300 from start to finish. You’ll learn how to read diagnostic trouble codes (DTCs), understand what they mean, and take appropriate action—whether that’s a quick fix at home or a trip to the mechanic. By 2026, with advancements in automotive technology and increased availability of affordable diagnostic tools, checking your engine light has never been easier or more accessible for everyday drivers.
Whether you’re a seasoned DIYer or a first-time car owner, this step-by-step guide will empower you to respond confidently when that little orange light pops up on your dashboard. Let’s get started.
Step 1: Recognize the Check Engine Light
Before you can check the engine light, you need to know what it looks like and what it’s trying to tell you. In the 2016 Chrysler 300, the check engine light appears as a symbol of an engine outline, usually glowing amber or orange on the instrument cluster.
Visual guide about How to Check Engine Light 2016 300
Image source: dodgecheckenginelight.com
What Does the Light Mean?
The check engine light indicates that your vehicle’s onboard diagnostic system (OBD2) has detected a problem. This could range from something minor—like a loose gas cap—to more serious issues such as a failing oxygen sensor or engine misfire. The OBD2 system monitors various components related to emissions, performance, and engine health.
Solid vs. Flashing Light
Pay close attention to how the light behaves:
- Solid (steady) light: This usually means a non-urgent issue that should be checked soon but doesn’t require immediate stopping. Examples include a faulty oxygen sensor or minor emissions problem.
- Flashing light: This is a red flag. A flashing check engine light typically indicates a severe misfire that can damage the catalytic converter. If you see this, reduce speed, avoid heavy acceleration, and get your car inspected as soon as possible.
Understanding these differences helps you assess the urgency and decide your next steps.
Step 2: Gather Your Tools
To check the engine light on your 2016 Chrysler 300, you’ll need a few basic tools. The most important is an OBD2 scanner—a handheld device that reads diagnostic trouble codes from your car’s computer.
Types of OBD2 Scanners
There are several options available in 2026, ranging from budget-friendly models to advanced Bluetooth scanners that connect to your smartphone:
- Basic code readers: These display trouble codes and allow you to clear them. They’re inexpensive (around $20–$40) and great for simple diagnostics.
- Bluetooth OBD2 adapters: These plug into your car and connect to apps like Torque Pro or OBD Fusion on your phone. They offer real-time data, code reading, and graphing capabilities. Prices range from $25 to $60.
- Professional-grade scanners: Used by mechanics, these offer advanced diagnostics but are overkill for most home users.
Other Helpful Tools
- A flashlight (to help locate the OBD2 port)
- Your vehicle’s owner’s manual (for reference)
- A notebook or phone to record codes and notes
For most drivers, a Bluetooth OBD2 adapter paired with a free or low-cost app is the best balance of functionality and affordability.
Step 3: Locate the OBD2 Port in Your 2016 Chrysler 300
The OBD2 port is the gateway to your car’s diagnostic system. In the 2016 Chrysler 300, it’s typically located under the dashboard on the driver’s side, just below the steering column.
Finding the Port
Here’s how to locate it:
- Sit in the driver’s seat and look down toward the floor.
- Move your hand along the underside of the dashboard, near the pedals.
- You’re looking for a 16-pin connector—usually black or gray—about the size of a small rectangular plug.
- It’s often tucked slightly behind the steering column but should be easily accessible without removing panels.
If you can’t find it, consult your owner’s manual or search online for “2016 Chrysler 300 OBD2 port location.” Some models may have it slightly to the left or right, but it’s almost always within arm’s reach from the driver’s seat.
Tip: Use a Flashlight
The area can be dark, especially if your car has dark interior trim. A small flashlight helps you spot the port quickly and avoid frustration.
Step 4: Connect the OBD2 Scanner
Once you’ve located the port, it’s time to connect your scanner and read the codes.
How to Plug In the Scanner
- Ensure your car is turned off before connecting the scanner.
- Insert the OBD2 scanner’s plug firmly into the port. It only fits one way, so don’t force it.
- Turn the ignition to the “ON” position (but don’t start the engine). This powers up the car’s computer and allows the scanner to communicate with it.
- Wait a few seconds for the scanner to initialize. Most devices will display a welcome screen or prompt you to select options.
Using a Bluetooth Scanner
If you’re using a Bluetooth adapter:
- Plug the adapter into the OBD2 port.
- Turn the ignition to “ON.”
- Open your diagnostic app (e.g., Torque Pro) on your smartphone.
- Enable Bluetooth on your phone and pair it with the adapter (usually labeled “OBDII” or similar).
- The app should automatically connect and display live data or prompt you to scan for codes.
Once connected, you’re ready to retrieve the trouble codes.
Step 5: Read the Diagnostic Trouble Codes (DTCs)
The OBD2 scanner will display one or more diagnostic trouble codes (DTCs). These five-character codes (like P0300 or P0420) pinpoint the system or component causing the check engine light to illuminate.
Understanding the Code Format
Each DTC follows a standard format:
- First character: Indicates the system (P = Powertrain, B = Body, C = Chassis, U = Network)
- Second character: Identifies whether it’s a generic (0) or manufacturer-specific (1) code
- Third character: Specifies the subsystem (e.g., 1 = fuel and air metering, 3 = ignition system)
- Last two characters: Define the specific fault
For example, P0300 means “Random/Multiple Cylinder Misfire Detected”—a common issue in the 2016 300.
Common Codes in the 2016 Chrysler 300
Here are some frequently encountered codes and what they mean:
- P0420: Catalyst System Efficiency Below Threshold (Bank 1) – Often due to a failing catalytic converter or oxygen sensor.
- P0300: Random/Multiple Cylinder Misfire – Could be caused by bad spark plugs, ignition coils, or fuel injectors.
- P0171: System Too Lean (Bank 1) – Indicates a vacuum leak or faulty mass airflow (MAF) sensor.
- P0440: Evaporative Emission Control System Malfunction – Often triggered by a loose or damaged gas cap.
- P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) – Suggests a stuck-open thermostat.
Use your scanner’s built-in code definitions or search online for detailed explanations. Many apps provide plain-language descriptions to help you understand the issue.
Step 6: Research and Diagnose the Problem
Once you have the code, it’s time to dig deeper. Don’t assume the code tells the whole story—it only points to a system, not necessarily the exact failed part.
Use Reliable Resources
Consult trusted sources such as:
- Repair manuals (e.g., Haynes or Chilton for the 2016 Chrysler 300)
- Online forums (like Chrysler-specific communities on Reddit or CarTalk)
- YouTube tutorials (search “2016 Chrysler 300 P0300 fix”)
- Official service bulletins from Chrysler
Example: Diagnosing P0300
If you get a P0300 code, start with these steps:
- Check spark plugs: Remove and inspect them for wear, fouling, or incorrect gap.
- Test ignition coils: Use a multimeter or swap coils between cylinders to see if the misfire follows the coil.
- Inspect fuel injectors: Listen for clicking sounds or use a noid light to test operation.
- Look for vacuum leaks: Spray carb cleaner around intake hoses while the engine runs—if RPMs change, you’ve found a leak.
Many P0300 issues in the 2016 300 are resolved by replacing spark plugs and coils, which are relatively inexpensive and easy to install.
When to Seek Professional Help
Some problems require specialized tools or expertise. If you’re dealing with:
- Internal engine issues (e.g., compression loss)
- Transmission or ABS-related codes
- Complex electrical faults
It’s best to consult a certified mechanic. They have access to advanced diagnostic equipment and factory service information.
Step 7: Fix the Issue (If Possible)
For common, straightforward problems, you may be able to fix the issue yourself.
Simple Fixes You Can Do at Home
- Tighten or replace the gas cap: A loose cap is a frequent cause of P0440. Turn it until it clicks three times.
- Replace spark plugs: The 2016 300 typically uses iridium plugs with a 100,000-mile lifespan, but they can fail early.
- Clean the MAF sensor: Use MAF cleaner spray to remove dirt and debris affecting air flow readings.
- Replace a faulty oxygen sensor: Located in the exhaust system, these sensors degrade over time and affect fuel mixture.
Tools and Parts Needed
Depending on the repair, you might need:
- Socket wrench set
- Spark plug socket (5/8” or 13/16”)
- Torque wrench (for proper plug tightening)
- Replacement parts (plugs, coils, sensors)
Always disconnect the battery before working on electrical components to avoid short circuits.
Safety First
Never work on a hot engine. Allow the car to cool completely before removing components. Wear safety glasses and gloves when handling chemicals or sharp parts.
Step 8: Clear the Check Engine Light
After fixing the problem, you’ll want to clear the trouble code and turn off the check engine light.
Using the OBD2 Scanner
- Reconnect the scanner to the OBD2 port.
- Turn the ignition to “ON.”
- Navigate to the “Clear Codes” or “Erase DTCs” option on the scanner.
- Confirm the action. The scanner will send a command to reset the ECU.
- The check engine light should turn off immediately.
Alternative Method: Disconnect the Battery
If you don’t have a scanner, you can reset the system by disconnecting the battery:
- Turn off the engine and remove the key.
- Disconnect the negative (-) battery terminal using a wrench.
- Wait 15–30 minutes to allow the ECU to fully reset.
- Reconnect the terminal and start the car.
Note: This method may also reset radio presets, clock, and other settings. It’s less precise than using a scanner, as it doesn’t confirm the code was cleared.
Step 9: Monitor the Light
After clearing the code, drive your car normally for a few days. The check engine light may stay off—or it might return.
Why the Light Might Come Back
- The underlying issue wasn’t fully resolved.
- A new problem has developed.
- The vehicle needs to complete a drive cycle for the ECU to re-test systems.
Drive Cycle Basics
A drive cycle is a series of driving conditions that allow the car’s computer to run self-tests. For the 2016 300, a typical drive cycle includes:
- Cold start (engine below 50°F)
- Idle for 2–3 minutes
- Accelerate to 55 mph and cruise for 5 minutes
- Decelerate without braking
- Repeat 2–3 times
Completing a drive cycle helps ensure all monitors are ready, which is especially important if you’re preparing for an emissions test.
Troubleshooting Common Issues
Even with the right tools, you might run into problems. Here’s how to handle common hurdles.
Scanner Won’t Connect
- Ensure the ignition is in the “ON” position.
- Check that the OBD2 port is clean and undamaged.
- Try a different scanner or app to rule out device failure.
- Verify the car’s battery has sufficient voltage (low voltage can prevent communication).
Codes Keep Returning
- The repair may have been incomplete.
- There could be multiple related issues (e.g., a bad coil causing a misfire that damages the catalytic converter).
- Intermittent faults (like a loose wire) may not trigger a code every time.
In these cases, professional diagnosis is recommended.
Light Won’t Clear
- Some codes require the problem to be fixed before they can be cleared.
- The ECU may need to complete a drive cycle.
- The scanner may not have the capability to clear certain codes.
Preventing Future Check Engine Light Issues
The best way to avoid check engine light surprises is through regular maintenance.
Follow the Maintenance Schedule
Refer to your 2016 Chrysler 300 owner’s manual for recommended service intervals. Key items include:
- Oil and filter changes every 6,000–7,500 miles
- Spark plug replacement every 100,000 miles (or sooner if issues arise)
- Air filter replacement every 15,000–30,000 miles
- Fuel system cleaning every 30,000 miles
Use Quality Fuel and Parts
Cheap fuel or aftermarket parts can lead to sensor errors and performance issues. Stick to top-tier gasoline and OEM or high-quality aftermarket components.
Address Small Problems Early
A minor issue like a weak battery or dirty air filter can escalate into a check engine light trigger. Stay proactive.
Conclusion: Stay Informed, Stay Safe
Knowing how to check the engine light on a 2016 Chrysler 300 puts you in control of your vehicle’s health. With an OBD2 scanner and a little know-how, you can diagnose problems, make informed decisions, and save money on unnecessary repairs.
Remember, the check engine light is a warning—not a death sentence. Most issues are fixable, especially when caught early. Whether you clear a P0440 with a new gas cap or tackle a P0300 with fresh spark plugs, you’re building confidence and competence as a car owner.
By 2026, automotive diagnostics have become more accessible than ever. Take advantage of the tools and resources available to keep your 2016 300 running smoothly for years to come. When in doubt, consult a professional—but don’t let the check engine light intimidate you. You’ve got this.