RAM 1500 Check Engine Light: Causes, Codes & Solutions

Seeing a warning light on your RAM 1500’s dashboard can be unsettling, especially when you’re not sure what triggered it. Is it safe to keep driving? Should I get this checked out immediately? What will happen if I don’t?

In this guide, we’ll walk you through the meaning behind the check engine light on your RAM 1500, explore the most common causes, and explain when scheduling service with a certified RAM technician near you is the smart next step.

What Does Your Check Engine Light Mean?

Your RAM’s check engine light is one of the most alarming warning lights on your vehicle’s dashboard, since it typically means that the engine may be nearing red-alert levels.

Vehicles have their own form of communication, known as the onboard diagnostics system. This system is made up of all the lights and symbols on your RAM’s dashboard, and each one indicates a vehicle issue or malfunction.

The check engine light, or CEL, is often depicted as an engine block icon or as specific words like “check engine.” A solid check engine light on the RAM 1500 indicates a serious, though not urgent, issue. However, if the check engine light is flashing, you need immediate repair or diagnosis.

Common Causes for the Check Engine Light to Illuminate (And Their Solutions)

The check engine light on your RAM 1500’s dashboard may come on for several reasons, from a loose gas cap to a more serious issue with the catalytic converter.

Here are some of the most common reasons your RAM 1500’s check engine light has turned on:

Loose or Damaged Gas Cap: One of the most common causes of a check engine light is a cracked or improperly sealed gas cap, which can allow fuel vapors to escape and trigger the light.

Solution: Make sure the gas cap is tightened securely, or replace it if it’s damaged. The light should turn off shortly after the cap is tightened or replaced.

Faulty Oxygen Sensor (O2 Sensor): The oxygen sensor monitors the amount of unburned oxygen in your RAM’s exhaust and helps regulate the fuel-air mixture. A faulty sensor can decrease fuel efficiency and increase emissions. Solution: Sensor replacement, which is usually less expensive than other repairs.
Catalytic Converter Issues: The catalytic converter helps reduce harmful emissions. If it's malfunctioning, your RAM will produce higher emissions and may even fail a smog test. Signs include a noticeable drop in fuel economy and a sulfur-like smell from the exhaust.

Solution: Replace the catalytic converter.

Mass Airflow Sensor (MAF) Failure: The MAF sensor measures the amount of air entering the engine to determine the proper fuel mixture. A malfunctioning MAF sensor can lead to poor fuel economy, stalling, and engine hesitation. Solution: Clean or replace the MAF sensor.
Worn Spark Plugs or Ignition Coils: Spark plugs and ignition coils, which are essential for engine combustion, can wear out over time. When they do, this leads to engine misfires and rough idling. If left unaddressed, it can damage the catalytic converter.

Solution: Replacing spark plugs and ignition coils at recommended service intervals is crucial for smooth engine performance.

Vacuum System Leaks: The vacuum system supports various engine functions, and a leak can cause issues such as high idle speed or misfires. Symptoms of a vacuum leak include a hissing sound from under the hood or stalling. Solution: Leaks often occur in hoses and seals, which can be repaired or replaced.
Battery and Charging System Problems: While this isn’t a direct engine issue, a failing battery or charging system can trigger the check engine light. Signs include difficulty starting your RAM or electrical components not working correctly. Solution: Check battery connections and the charging system. You may need a replacement.

Understanding the RAM 1500 Check Engine Light Codes

The first step to addressing the “check engine” light on your RAM 1500 is to run a diagnostic test using an OBD-II scanner. An OBD-II (On-Board Diagnostics) scanner is used to retrieve diagnostic trouble codes (DTCs) that help you understand the issue that’s happening within your vehicle’s engine.

Here are some of the most common OBD 2 codes for your RAM 1500, and what they mean:

Code	Name	Description
P0171	System Too Lean Bank 1	Potential failure of the oxygen sensor, or an issue with the air-fuel mixture
P0174	System Too Lean Bank 2	Indicates similar intake leaks or sensor issues to P0171, but affects the opposite side of the engine
P0300	Random/ Multiple Cylinder Misfire Detected	Indicates an engine misfire in one or more cylinders
P0301-P0308	Cylinder Specific Misfire Detected	Indicates an engine misfire in a specific cylinder, often caused by faulty spark plugs, fuel injector, or a coil pack
P0420	Catalyst System Efficiency Below Threshold	Issue with the catalytic converter
P0455	Evaporative Emission Control System Large Leak Detected	The fuel cap is possibly loose, or there is a larger issue with the RAM’s emissions system
P0456	Evaporative Emission System Leak Detected (Small Leak)	Could be a minor fuel-system leak, often related to the gas cap.
P0440	Evaporative Emission Control System Malfunction	Indicates an issue with the system that captures fuel vapors to prevent them from being released into the atmosphere.
P0442	Small EVAP System Leak	A minor EVAP leak that could affect fuel efficiency and emissions over time
P0128	Coolant Thermostat Below Operating Temperature	A stuck-open thermostat may cause the engine to fail to reach optimal operating temperature
P0110-P0113	Faulty Intake Air Temperature Sensor	Engine computer is failing to read the incoming air temperature, which could affect performance and efficiency
C1210	ABS Pump Motor Overrun	Issue with the anti-lock braking system

These scanners are available at most dealership service centers, and some dealers offer free diagnostic scanning. Once the codes are retrieved from your RAM’s OBD-II port, you can look up their meaning or consult a certified mechanic at a RAM service center for the next steps.

How to Complete a RAM 1500 Check Engine Light Reset

If you’ve diagnosed and resolved the underlying issue, the final step is to reset the light.

Here are several ways to reset it:

Use an OBD-II Scanner: The easiest way to clear the error codes is to use an OBD-II scanner. Plug the scanner into the diagnostic port, usually located under the dashboard, and follow the instructions to clear the codes.
Disconnect the Battery: If you don't have a code reader, disconnect the negative battery cable for about 15 minutes. This will reset the engine control module and turn off the check engine light. Remember to reconnect the cable securely.
Drive and Wait: Sometimes the light will reset itself after several drive cycles if the problem has been resolved. This method requires patience and time.

If you don’t feel comfortable resetting the check engine on your RAM 1500, stop by Santee Chrysler Dodge Jeep RAM for help!

Please note that resetting your check engine light is not recommended for beginners or those without some automotive knowledge. Our certified technicians understand your RAM inside and out. We are happy to assist in getting you back on the road safely and confidently!

Discover RAM 1500 Maintenance & Repairs You Can Count on at Santee CDJR

Our factory-trained RAM technicians specialize in diagnosing and repairing RAM models, from the 1500 to the heavy-duty pickups. With access to cutting-edge diagnostic equipment and genuine OEM parts, our team can quickly identify the issue, make the necessary repairs, and help you get back on the road safely.

With regular maintenance services, including oil changes and spark plug replacements, we can help ensure that your RAM is well-prepared for the road ahead. Schedule an appointment for RAM service near you online today, or visit us in Manning, SC!

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