Ram 3500 Has A Check Engine Light

Troubleshooting Common Causes for the Check Engine Light in Your Ram 3500 and How to Resolve Them

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Emissions System
0%
60% chance it's
Something else
The most common reasons a Ram 3500 has a check engine light are an emissions system component, a sensor, or a catalytic converter.
  • Emissions System: A faulty emissions system component, such as an oxygen sensor or EGR valve, can lead to increased emissions and trigger the check engine light.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a Ram 3500 has a check engine light?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A faulty oxygen sensor is one of the most common causes of a check engine light. Symptoms may include a decrease in fuel mileage, hesitation or misfiring from the engine, rough idling or even stalling. A faulty sensor may cause the vehicle to fail an emissions test.

Any time there is an emissions fault the check engine light will be displayed. The purpose of the check engine light is to inform the driver that an emission related fault has been found, and that there are on-board diagnostic (OBD) trouble codes stored in the powertrain or engine control module. Additionally, since the emissions systems are so intertwined into engine control and transmission control systems, symptoms may include nearly any sort of drivability concerns. This may include harsh shifting, failure to shift, hesitation on acceleration, jerking, engine failure to start or run, loss of power, or any number of other drivability issues.

Due to the nature of electrical systems on modern vehicles, the range of problems these can cause are nearly limitless. However, there is a way to categorize them in two ways. Permanent and intermittent problems. Permanent problems appear and remain. This may be the vehicle will not start, the radio does not work, or the door chime will not turn off among many, many others. These problems are more straight-forward to diagnose since they present themselves at all time. This means there will always be a fault to find. Intermittent electrical problems, however, can be difficult or impossible to locate, since they appear then disappear without warning. The best case scenario for an intermittent issue is when replicating the problem is easily accomplished and understood. This allows a technician to make an issue semi-permanent, allowing them to find the fault. Other issues that come and go without warning and cannot be replicated on demand must occur when the technician is servicing the vehicle, otherwise there is no problem to correct. It is most important to understand that electrical system faults always require inspection, and can include the vehicle working in any manner, or not working at all.

Like we noted in the last section, general diagnosis symptoms are the most vague of the bunch. There are several diagnostic spectrums, electrical diagnosis, drivability diagnostics, engine diagnostics, transmission diagnostics, and the list could continue for about 5 or 10 more spectrums of diagnostics. The most important take-away here, is that general diagnostics are diagnostics that have no other spectrum in which they fit, or the problem is unknown. This means that any vehicle left outside of a repair facility with the keys and an authorization to perform diagnosis will be diagnosed under the general diagnosis spectrum.

When the Check Engine Light comes on, you may experience engine performance issues such as poor acceleration, rough idling, or an engine that won't start. In some cases, no abnormal symptoms will be experienced. Other systems like the transmission or ABS can cause the Check Engine Light to illuminate and lights for those systems can come on at the same time. Similar lights may say "Check Engine Soon", "Malfunction Indicator Light" or just "Check". In rare case the engine can overheat.

Troubleshooting Check Engine Light in a Ram 3500

When faced with a check engine light in your Ram 3500, the first step is to pull the trouble codes using an OBD-II scanner. This tool will provide specific codes that indicate the underlying issues, allowing you to focus your efforts on the most likely culprits. Common problems include ignition cylinder issues and faulty oxygen sensors, which can often be resolved with straightforward fixes. After addressing the identified problem, it’s essential to drive the vehicle for a short distance to allow the onboard diagnostics system to recognize the repair. If the light remains illuminated, consider resetting the powertrain control module (PCM) to clear any lingering codes. Remember, while some issues may seem minor, neglecting the check engine light can lead to more significant performance problems or damage, so it’s crucial to act promptly. By following this structured approach, you can effectively diagnose and resolve the check engine light issue, ensuring your Ram 3500 runs smoothly and efficiently.

What Could Cause the Check Engine Light to Illuminate in a Ram 3500?

When the check engine light comes on in a Ram 3500, it can indicate a range of issues that may require your attention. Common problems include malfunctions in the emissions system, which can stem from faulty components that affect vehicle performance and environmental compliance. Additionally, issues with sensors, particularly the mass airflow sensor, can disrupt the engine's air-fuel mixture, leading to poor efficiency and performance. The catalytic converter is another critical component that, if malfunctioning, can cause significant engine problems and should be inspected. Ignition cylinder issues may also lead to irregular engine running, while a malfunctioning exhaust gas oxygen sensor can result in misfires, especially during acceleration or at low RPMs. Other potential culprits include a faulty oxygen sensor, low oil pressure, or even a simple gas cap problem, such as being loose or damaged. If the check engine light is flashing, it is crucial to avoid driving the vehicle and seek professional help immediately. Once the underlying issue is resolved, you can reset the light by disconnecting the battery for about 30 seconds, allowing you to continue your DIY journey with confidence.

Why is the Check Engine Light On in a Ram 3500?

When the Check Engine Light illuminates in your Ram 3500, it’s crucial to address the underlying issues promptly to avoid serious consequences. Ignoring this warning can lead to significant engine damage, costly repairs, and even safety hazards on the road. For instance, a simple fix like tightening or replacing a loose gas cap can prevent unnecessary fuel evaporation and emissions issues. However, if the light indicates a more severe problem, such as a faulty ignition cylinder or a severe engine misfire, immediate attention is essential. A flashing Check Engine Light signals a critical misfire that can damage the engine, catalytic converter, and oxygen sensors if left unchecked. Therefore, it’s vital to diagnose and resolve the cause of the light as soon as possible, ensuring your vehicle remains safe and operational. If you’ve successfully fixed the issue, remember to reset the light by disconnecting the battery, which can help you monitor any future problems effectively.

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