ISX12 for Motorhome (EPA 2010)


ISX12 for Motorhome (EPA 2010)
ISX12. Better. From Start To Finish.

Cummins ISX12 builds on the legacy of the ISM and proven technology of the ISX15 to deliver better fuel economy, performance, reliability and durability. It has more horsepower and more torque, plus stronger acceleration – all in a compact design. It achieves near-zero emissions and reduces noise output. With 450-500 hp (336–373 kW), power output is a perfect match for every kind of motorhome.

Optimized calibrations have resulted in significant fuel economy gains for the ISX12 versus the ISX11.9.

Cummins is the only engine manufacturer to design and develop, manufacture and support every component from the air intake to the exhaust aftertreatment in a totally integrated system.

The XPI fuel system is capable of the highest injection pressures in the industry, with a common-rail design that delivers strong performance independent of engine speed. The integrated system of the ISX12 also includes a VGT™ Turbocharger custom-built by Cummins Turbo Technologies.

The Cummins Aftertreatment System on the ISX12 combines a proprietary Cummins Particulate Filter with our Selective Catalytic Reduction (SCR) technology, functioning as a single unit. Designing and building the package in-house allows Cummins to calibrate the engine for optimum performance and near-zero emissions. The high efficiency of the aftertreatment frees the engine to generate higher horsepower while also saving fuel. Improved fuel economy not only lowers fuel consumption – it also reduces greenhouse gas (GHG) emissions.Cummins ISX12 delivers strong pulling power, excellent throttle response and high fuel economy numbers.

And that's just the start of all the features the ISX12 has to offer.  Every element has been designed and manufactured to optimize performance and minimize maintenance for superior driveability.

All backed by the best customer support in the business.

Plus, you get exclusive Cummins programs like Coach Care™ to meet your service needs as you travel across North America in your motorhome. All backed by the most extensive customer support network in North America.

For Cummins-branded merchandise, electronic tools, literature and more, visit our PowerStore web site.


Cummins PowerSpec is an electronic tool that makes it possible to tailor the operation of Cummins engines in every on-highway application.

Available for: On-Highway, Recreational Vehicle, Motorhome Engines

See ISX PowerSpec Engine Features


Advertised Horsepower  500 hp  373 kW 
Peak Torque  1645 lb-ft  2232 N•m 
Governed Speed  2100 rpm
Clutch Engagement Torque  800 lb-ft  1085 N•m 
Number of Cylinders   6
Oil System Capacity  12 U.S. gallons  45.4 liters 
System Weight  2,888 lb  1,310 kg 
Engine (Dry)  2,666 lb  1,209 kg 
Aftertreatment System*  222 lb  101 kg 
*Increase over standard muffler and does not include chassis OEM-supplied components

Product Finder Specifications

Certification Level EPA 2010
Power 450 - 500 hp / 336 - 373 kW
Torque 1550 - 1645 lb-ft / 2102 - 2230 N•m


Advertised Horsepower (kW) Peak Torque lb-ft (N•m) @ rpm
450 HP (336 KW)  1550 lb-ft (2103 NM)
500 HP (373 KW)  1645 lb-ft (2232 NM)


XPI Fuel System - Delivers a precise quantity of fuel at ultra-high pressures.  This, together with more robust electronic engine controls, enables multiple injection events per cycle. 

Compact Design - Compact and powerful, with plenty of torque to pull every load while delivering optimum fuel economy.  It shares many major components with the ISX15, so it’s strong enough to handle virtually any application.

VGT™ Turbocharger - Enhanced response and control with electric actuation for infinite adjustment, providing exact boost at any rpm. Sliding-nozzle design increases reliability and durability.

Cooled EGR - Next-generation system lowers combustion temperatures for reduced emissions and optimized fuel economy.

Fully Integrated Electronic Controls – A single, higher-capacity Electronic Control Module (ECM) controls everything from air intake to exhaust aftertreatment for peak performance and near-zero emissions.

Cummins Aftertreatment System - The proven Cummins Particulate Filter reduces particulate matter by over 90%.  In 2010 it is combined with Cummins Selective Catalytic Reduction (SCR) to meet emission standards while maintaining best-in-class performance, reliability and durability.


Duty Cycles*  Miles / Kilometers Months  
Oil and Filter  15,000 mi (with CJ4 oil)
24,000 km
Fuel Filter  15,000 mi (with CJ4 oil)
24,000 km
Coolant Filter**  50,000 mi
80,000 km 
Valve Adjustment  250,000 mi
400,000 km 
Coalescing Filter  125,000 mi 240,000 km  
Hydrocarbon Doser Injector Cleaning  150,000 mi
240,000 hm 
DEF Filter  200,000 mi (320,000 km) 
Particulate Filter Cleaning  300,000 mi
(480,000 km) 

For complete maintenance information, please consult your Owner's Manual or Operations and Maintenance Manual.

Brochures Available

Title Bulletin Number Request View  
NRP - DPF There Is A Difference Brochure 5410774 Request View  Download
NRP - DPF There Is A Difference Brochure (French) 5410815 Request View  Download
NRP - DPF There Is A Difference Brochure (Spanish) 5410816 Request View  Download
ReCon DPF Flyer 2878897 Request View  Download
ReCon DPF Flyer - French 5410632 Request View  Download
ReCon DPF Flyer - Spanish 5410633 Request View  Download