How to reset check engine light on cummins isx

How To Reset Check Engine Light on Cummins ISX

Are you tired of seeing that pesky “Check Engine” light illuminated on your Cummins ISX engine? Fret not!

To reset the check engine light on your Cummins ISX, first, locate the diagnostic port. Then, connect a compatible tool and access the ECM. Click clear fault codes. Finally, start the engine and monitor for any issues.

As I faced the same issue, I researched to find a solution. In this article, I will explain how I successfully reset the check engine light on Cummins ISX as a step-by-step process. Say goodbye to irritation and hello to a smoother engine.

Let’s dive in!

What is Cummins ISX?

The Cummins ISX is a powerful inline 6-cylinder turbodiesel engine known for its impressive performance, delivering approximately 600 horsepower and 2050 pounds-feet of torque.

This engine is widely utilized in various heavy-duty vehicles, such as the Freightliner M2 and the International DT-466. It has taken over the renowned N14 engine previously manufactured by Cummins, becoming its successor.

The engine is strong in addition to having superior torque and horsepower for trucks. The ISX engine, however, is susceptible to numerous issues, just like many other engines.

Why does the Cummins ISX’s Check Engine Light Come On?

The check engine light comes on when the internal computer detects an issue with the engine or transmission.

Fuel Pump ProblemsRough idling Excessive smoke from the exhaust
Extended cranking during startup
Loose Flywheel Cap ScrewsImproperly torqued cap screws that may come loose
Fuel Filter CloggingClogging primarily in cold weather
EGR and DPF ProblemsSticking EGR valves and carbon buildup
Power loss and poor running conditions

Let’s discuss them one by one.

Fuel Pump Problems

When it comes to the ISX engine, the fuel pump emerges as a prevalent issue. Keep an eye out for signs such as rough idling, excessive smoke billowing from the exhaust, and prolonged cranking during startup.

While there was a recall to address fuel pump problems, it’s advisable to inspect your fuel pump if you encounter any of these symptoms.

Loose Flywheel Cap Screws

Reports indicate that the cap screws responsible for securing the flywheel to the camshaft or crankshaft may not have been adequately torqued, potentially resulting in their loosening over time. Such a situation can cause serious engine damage.

A recall has been issued regarding this matter, underscoring the importance of verifying whether your engine is affected and promptly addressing the issue.

Fuel Filter Clogging

A matter that seems to afflict Cummins engines, especially in colder weather, is fuel filter clogging. This occurrence can have adverse effects on engine performance and might necessitate frequent fuel filter replacements.

It remains uncertain whether this issue is inherent to Cummins engines themselves or relates to the specific type of fuel filter employed.

EGR and DPF Problems

Similar to other manufacturers, Cummins engines equipped with Exhaust Gas Recirculation (EGR) and Diesel Particulate Filter (DPF) systems may encounter challenges. Sticking EGR valves and the accumulation of carbon deposits can lead to power loss and subpar running conditions.

To mitigate EGR problems, it is recommended to abstain from idling the engine for extended periods. By doing so, you can minimize the risk of valve obstructions and optimize the performance of these emission control systems.

How did I Reset the Check Engine Light on Cummins ISX?

I started by ensuring that the engine was turned off. I parked the truck in a safe and well-ventilated area.

Next, I located the diagnostic port. On the Cummins ISX engine, it is typically found near the engine control module (ECM). I consulted the vehicle’s manual to confirm its exact location.

Then I connected the diagnostic tool to the port, making sure that it was compatible with the Cummins ISX engine and capable of accessing the ECM.

Once the connection was established, I powered on the diagnostic tool. I followed the prompts on the tool’s display to access the ECM and cleared the fault codes by selecting the option “clear faulty codes”.

I waited for a few moments as the diagnostic tool communicated with the ECM and cleared the codes. Once completed, the check engine light is turned off.

I disconnected the diagnostic tool from the diagnostic port.

Finally, I started the engine and ensured that the check engine light remained off. I monitored the vehicle’s performance for any new fault codes or issues that might arise.

Congratulations! You have successfully reset the check engine light on your Cummins ISX engine. Remember to address any underlying issues that may have caused the fault codes initially, such as sensor replacements or repairs.

Note: It’s important to understand that resetting the check engine light only clears the codes temporarily. If there are ongoing issues with the engine, the light will likely illuminate again until the problem is resolved.


Who manufactures Cummins ISX diesel engines?

For heavy-duty trucks and motor coaches, Cummins produces inline 6-cylinder diesel engines under the X-series name. The N14 diesel engine was replaced by the Cummins X-series engine in 2001 when the EPA passed emissions regulations, rendering the N14 out of date.

How long does a Cummins ISX last?

For this kind of engine, the Cummins ISX has been known to last for over 500,000 miles in some cases. One of the top advantages of this engine is how long it lasts. This engine can go up to 15,000 miles without a filter or oil change.

Is Cummins a turbo?

Yes, it is. The advantages of a new VGT—increased engine power, reduced emissions, and improved fuel efficiency can be obtained with this turbo without the high cost.

What turbo size does the Cummins ISX have?

The HE400VG/HE451VE turbocharger for Cummins ISX and QSX engines deserves praise. This replacement turbo offers you a brand-new, dependable replacement turbocharger to get you back on the road and is offered in both 64 and 67-mm designs.


The Cummins ISX engine is known for its power and reliability. But it is not immune to certain issues that may trigger the dreaded check engine light. However, understanding the common culprits can help you stay ahead of potential problems and keep your engine running smoothly.

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