Discover how to quickly and accurately check the check engine light on your 2016 Dodge Ram using built-in diagnostics, a code reader, or your smartphone. This guide walks you through every step to identify issues, understand error codes, and decide when to seek professional help.
Key Takeaways
- Understand what the check engine light means: It signals a problem with your engine, emissions, or onboard systems—don’t ignore it.
- Use the onboard diagnostic (OBD2) system: Your 2016 Dodge Ram has a built-in port that stores trouble codes when the light comes on.
- Get an OBD2 scanner or app: Affordable tools or smartphone apps can read codes and help pinpoint the issue.
- Interpret the trouble codes correctly: Codes like P0300 (random misfire) or P0420 (catalytic converter) guide your next steps.
- Clear codes after repairs: Use your scanner to reset the light once the problem is fixed—don’t just disconnect the battery.
- Know when to visit a mechanic: Some issues require professional diagnosis, especially if the light flashes or returns quickly.
- Prevent future warnings: Regular maintenance like oil changes, air filter replacements, and fuel system care reduce false alarms.
How to Check Check Engine Light 2016 Dodge Ram
If you’re driving a 2016 Dodge Ram and the check engine light suddenly pops up on your dashboard, don’t panic—but don’t ignore it either. This warning light is your truck’s way of saying something needs attention under the hood. Whether it’s a minor sensor glitch or a more serious engine issue, knowing how to check and respond to the check engine light can save you time, money, and potential breakdowns.
In this comprehensive guide, updated for 2026, we’ll walk you through everything you need to know about checking the check engine light on your 2016 Dodge Ram. You’ll learn how to read diagnostic trouble codes (DTCs), use affordable tools like OBD2 scanners, interpret what the codes mean, and decide whether you can fix the problem yourself or need to visit a mechanic. By the end, you’ll feel confident handling this common but often misunderstood warning.
Why the Check Engine Light Comes On
The check engine light—also known as the malfunction indicator lamp (MIL)—is part of your vehicle’s onboard diagnostics system (OBD2). When the engine control unit (ECU) detects a problem that could affect emissions or engine performance, it triggers the light and stores a trouble code. These codes help technicians (and you) identify the root cause.
Visual guide about How to Check Check Engine Light 2016 Dodge Ram
Image source: dodgecheckenginelight.com
Common reasons the light comes on in a 2016 Dodge Ram include:
- A loose or faulty gas cap
- Oxygen (O2) sensor failure
- Spark plug or ignition coil issues
- Catalytic converter problems
- Mass airflow (MAF) sensor malfunction
- Exhaust gas recirculation (EGR) valve issues
- Evaporative emissions system leaks
In 2026, with advanced vehicle diagnostics and smarter sensors, many of these issues can be detected earlier than ever. However, the basics remain the same: the light means “something’s not right.” The key is figuring out what—and how urgent it is.
Step 1: Assess the Light’s Behavior
Before you start scanning for codes, take a moment to observe how the light is behaving. This can give you a clue about the severity of the issue.
Solid (Steady) Check Engine Light
If the light is on but not flashing, it usually means there’s a problem that needs attention, but it’s not an emergency. You can typically drive safely to a repair shop or continue your trip—just don’t delay diagnosis. Common causes include a faulty oxygen sensor or a loose gas cap.
Flashing Check Engine Light
A flashing light is a red flag. It indicates a severe problem, such as a major engine misfire that could damage the catalytic converter. If you see this, pull over safely as soon as possible, turn off the engine, and call for roadside assistance or a tow. Continuing to drive could cause expensive damage.
Blinking or Intermittent Light
If the light turns on and off randomly, it may point to an intermittent issue—like a loose wire or a sensor that’s failing under certain conditions. Still, get it checked out as soon as convenient.
Pro Tip: Keep a small notebook in your glove box to log when the light comes on, what you were doing (e.g., accelerating, idling), and any unusual sounds or smells. This info can help mechanics diagnose the issue faster.
Step 2: Locate the OBD2 Port
To read the trouble codes, you’ll need access to your truck’s OBD2 port. This is a standardized 16-pin connector found in all vehicles made after 1996, including your 2016 Dodge Ram.
Where to Find It
In most Dodge Rams, including the 2016 model, the OBD2 port is located under the dashboard on the driver’s side. You’ll usually find it:
- Just below the steering column
- Behind a small plastic cover or panel
- Within arm’s reach when seated in the driver’s seat
It looks like a trapezoid-shaped plug with 16 metal pins inside. It may be labeled “OBD2” or “DLC” (Data Link Connector). If you can’t find it, check your owner’s manual or look for a small flap you can gently pry open with your fingers.
Note: Some trucks have the port tucked behind the center console or near the fuse box, but in the 2016 Ram, it’s almost always under the dash on the left side.
Step 3: Use an OBD2 Scanner to Read Codes
Now that you’ve found the port, it’s time to read the trouble codes. You’ll need an OBD2 scanner—a small handheld device that plugs into the port and communicates with your truck’s computer.
Types of OBD2 Scanners
In 2026, you have several options:
- Basic Code Readers: Affordable ($20–$50), these devices read and clear codes but offer limited details. Great for DIYers who just want to know what’s wrong.
- Advanced Scanners: Priced from $100–$300, these provide live data, freeze frame info, and can test sensors. Ideal for troubleshooting complex issues.
- Bluetooth OBD2 Adapters: These plug into the port and connect to your smartphone via Bluetooth. Pair them with apps like Torque Pro, OBD Fusion, or Car Scanner to view codes and data on your phone. Cost: $20–$60.
For most 2016 Dodge Ram owners, a Bluetooth adapter paired with a free or low-cost app is the best balance of price, convenience, and functionality.
How to Use a Bluetooth OBD2 Adapter
- Plug the adapter into the OBD2 port under the dashboard.
- Turn the ignition to the “ON” position (you don’t need to start the engine).
- Open your smartphone’s Bluetooth settings and pair it with the adapter (usually named something like “OBDII” or “ELM327”).
- Launch your OBD2 app (e.g., Torque Pro).
- Tap “Connect” or “Scan” to read the trouble codes.
The app will display one or more diagnostic trouble codes (DTCs), usually in the format PXXXX (e.g., P0301). These codes tell you exactly what system or component is malfunctioning.
Example: If you see P0455, it means there’s a large evaporative emissions leak—often caused by a loose or damaged gas cap.
Step 4: Interpret the Trouble Codes
Once you have the code, it’s time to figure out what it means. Here’s how to decode the most common ones in a 2016 Dodge Ram.
Understanding Code Structure
All OBD2 codes follow a standard format:
- P = Powertrain (engine, transmission, emissions)
- B = Body (airbags, climate control)
- C = Chassis (ABS, suspension)
- U = Network/Communication
The first digit after the letter indicates the subsystem:
- 0 = Generic (SAE-defined)
- 1 = Manufacturer-specific (Chrysler/Dodge)
The last three digits specify the exact issue.
Common 2016 Dodge Ram Trouble Codes
Here are some frequent codes and what they mean:
- P0300: Random/Multiple Cylinder Misfire Detected – Could be spark plugs, coils, or fuel system.
- P0301–P0308: Misfire in a specific cylinder (e.g., P0301 = Cylinder 1 misfire).
- P0420: Catalyst System Efficiency Below Threshold (Bank 1) – Often a failing catalytic converter.
- P0440: Evaporative Emission Control System Malfunction – Check gas cap, hoses, or EVAP canister.
- P0171/P0174: System Too Lean (Bank 1 or 2) – Could be a vacuum leak, MAF sensor, or fuel pressure issue.
- P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) – Thermostat may be stuck open.
- P0455: Large EVAP Leak Detected – Usually a loose or missing gas cap.
Pro Tip: Use free online code databases like OBD-Codes.com or your OBD2 app’s built-in library to look up detailed explanations and repair suggestions.
Step 5: Diagnose and Fix Common Issues
Once you know the code, you can start diagnosing the problem. Some issues are easy to fix yourself; others require a mechanic.
Issue 1: Loose or Faulty Gas Cap
If you get a P0455 or P0440 code, start here. A loose gas cap is the #1 cause of check engine lights in modern trucks.
- Turn off the engine.
- Remove the gas cap and inspect it for cracks, worn seals, or damage.
- Reinstall it firmly—you should hear it click 3–5 times.
- Drive for a few days. If the light doesn’t return, the problem is solved.
Note: If the cap is damaged, replace it with an OEM or high-quality aftermarket cap. Cheap caps can cause leaks.
Issue 2: Oxygen (O2) Sensor Failure
Codes like P0130–P0167 indicate O2 sensor problems. These sensors monitor exhaust gases and help the engine adjust the air-fuel mixture.
- Symptoms: Poor fuel economy, rough idle, failed emissions test.
- Diagnosis: Use your OBD2 scanner to check live O2 sensor data. A stuck or slow sensor needs replacement.
- Repair: Replace the faulty sensor. Front (upstream) sensors are easier to access; rear (downstream) may require lifting the truck.
Cost: $50–$200 per sensor, plus labor if done by a shop.
Issue 3: Spark Plug or Ignition Coil Problems
Misfire codes (P0300–P0308) often point to ignition issues.
- Check spark plugs: Remove and inspect for fouling, wear, or incorrect gap.
- Test ignition coils: Use a multimeter or swap coils between cylinders to see if the misfire follows.
- Replace as needed. Use OEM or high-quality aftermarket parts.
Tip: Replace all spark plugs at once if one fails—prevents future issues.
Issue 4: Mass Airflow (MAF) Sensor Issues
Codes like P0101 or P0171 may indicate a dirty or faulty MAF sensor.
- Locate the MAF sensor (usually between the air filter and throttle body).
- Unplug it and clean it with MAF sensor cleaner (do not use compressed air).
- If cleaning doesn’t help, replace the sensor.
Warning: Never touch the delicate wires inside the MAF sensor—they break easily.
Step 6: Clear the Codes and Reset the Light
After fixing the issue, you’ll want to clear the trouble codes and turn off the check engine light.
How to Clear Codes
- Plug your OBD2 scanner or Bluetooth adapter back into the port.
- Turn the ignition to “ON.”
- In your scanner or app, select “Clear Codes” or “Reset MIL.”
- Confirm the action. The light should turn off.
Important: Do not simply disconnect the battery to reset the light. This can erase important adaptive learning data and may not clear all codes. Always use a scanner.
What If the Light Comes Back?
If the light returns after clearing, the problem wasn’t fully resolved. Re-scan for codes and re-diagnose. Some issues, like a failing catalytic converter, may require professional repair.
Step 7: Know When to Visit a Mechanic
While many check engine light issues can be handled at home, some require expert help—especially in 2026, when vehicles have more complex electronics.
When to Call a Professional
- The check engine light is flashing.
- You’re getting multiple or complex codes (e.g., P0300 + P0420).
- The problem involves the transmission, ABS, or airbags.
- You lack the tools or confidence to perform the repair.
- The issue affects drivability (e.g., stalling, loss of power).
Modern Dodge Rams have sophisticated systems, and improper repairs can lead to bigger problems. When in doubt, visit a certified Chrysler/Dodge technician or a trusted independent shop with experience in RAM trucks.
Troubleshooting Tips for 2026
As vehicles evolve, so do diagnostic tools and techniques. Here are some 2026-specific tips for checking your 2016 Dodge Ram’s check engine light:
Use Smartphone Integration
Many 2016 Rams can now connect to apps that provide real-time monitoring, maintenance reminders, and even predictive diagnostics. Apps like CarScanner or OBD Fusion can alert you to potential issues before the light comes on.
Check for Recalls or TSBs
Visit the NHTSA website or Dodge’s official site to see if your truck has any open recalls or technical service bulletins (TSBs) related to the check engine light. Some issues are known problems with factory fixes.
Update Your Scanner Software
OBD2 scanners and apps receive updates that improve code accuracy and add new features. Make sure your device’s firmware and app are up to date for the best results.
Consider a Professional Diagnostic Scan
Some auto parts stores (like AutoZone or O’Reilly) offer free code reading. However, their basic scanners may not access manufacturer-specific codes. For a full diagnosis, a professional scan at a dealership or repair shop may be worth the cost ($50–$100).
Preventing Future Check Engine Light Issues
The best way to deal with the check engine light is to avoid it altogether. Regular maintenance is key.
Follow Your Maintenance Schedule
Refer to your 2016 Dodge Ram owner’s manual for 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 30,000–100,000 miles (depending on type)
- Fuel system cleaning every 30,000 miles
- Inspect gas cap and EVAP system annually
Use Quality Fuel and Parts
Low-quality fuel or aftermarket parts can trigger false codes. Use Top Tier gasoline and OEM or reputable aftermarket components.
Keep the Engine Clean
Dirt and debris can clog sensors and airflow. Regularly clean the engine bay (gently) and inspect for leaks or damage.
Conclusion
Checking the check engine light on your 2016 Dodge Ram doesn’t have to be intimidating. With the right tools—like an OBD2 scanner or smartphone app—you can quickly read trouble codes, understand what they mean, and take action. Whether it’s a simple gas cap fix or a more complex sensor issue, this guide gives you the knowledge to handle it confidently.
Remember: a solid light means “check it soon,” but a flashing light means “stop now.” Don’t ignore the warning. And always clear codes properly after repairs—don’t just disconnect the battery.
By staying proactive with maintenance and using modern diagnostic tools, you’ll keep your 2016 Dodge Ram running smoothly for years to come. In 2026 and beyond, being informed is the best way to protect your investment and your safety on the road.