Uptime. Efficiency. Performance
You want it all.


Cummins ISX15 is designed for downspeeding, which simply means that your engine gets full power at a lower rpm. The slower your engine runs, the more miles you get out of every drop of diesel fuel - and every stroke you save reduces wear and adds life to your engine. And advanced engine control features such as SmartCoast™ stretch your fuel economy even further. If the truck you are replacing is six years old, spec'ing a new truck with the ISX15 SmartAdvantage™ Powertrain will increase your fuel economy by about 12 percent, saving you between $5,700 and $11,400 per truck in fuel costs every year.

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Most regional or cross-country routes that include some mountainous terrain require at least 1850 lb-ft of torque to maintain road speeds over the mountains and keep drivers happy. That kind of power used be available only in engines rated at 485 hp to 600 hp - and as the horsepower numbers went up, mpg went down. But now, Cummins ISX15 is being offered at three new ratings of 400 hp, 450 hp and 475 hp with 1850 lb-ft of peak torque. Higher horsepower ratings (up to 600 hp and 2050 lb-ft of peak torque) are still available for severe-duty applications, but these 1850 lb-ft fuel-efficiency ratings are ideal for customers who need big torque but don't want to sacrifice fuel economy.

Truckers with routes primarily across rolling or flat terrain - or pulling less than 80,000 lbs gross cargo vehicle weight (GCVW) - should spec one of the ISX15 SmartTorque ratings with a peak torque of 1650-1750 lb-ft. This gives drivers the exact amount of power to run at maximim cruise speeds in top gear, while at the same time improving fuel economy. Of course, all ISX15 ratings still include the most powerful engine brake in the industry.


The Cummins ISX15 engine has been proven over the past two decades in every driving scenario imaginable. Continuous improvements focusing on reliability and durability have increased uptime and revenue-producing miles. This dedication to maximizing uptime goes beyond engine hardware to include everything from improved spec'ing tools to faster, more accurate servicing capabilities.

One of the most recent improvements is a built-in electronic feature called Connected Diagnostic™ that provides expert advice almost instantly to drivers if a fault code is triggered. In seconds, Cummins reviews vehicle operating data, assesses the root cause of the fault and tells drivers what to do. In most cases, drivers will be able to complete the delivery route without risking engine damage. You can even access this diagnostic information from your home office or on the go with the Connected Diagnostics mobile app. Information can also be sent directly to your authorized Cummins service provider, to ensure a fast and accurate repair and maximum uptime. Connected Diagnostics is compatible with a broad array of leading telematics providers, see cumminsengines.com/connected-diagnostics for the most current listing.

Cummins ISX15 continues to be the No. 1 choice

Connected Diagnostics

Connected Diagnostics


SmartCoast and Predictive Cruise Control


SmartAdvantage Powertrain Test Drive