ISX12 for Motorhome (2013)


ISX12 for Motorhome (2013)

Better In Every Way.

The Cummins ISX12 is built using proven technology from the heavy-duty ISX15 to deliver better  performance, reliability and durability for luxury motorhome owners. Rated at up to 500 horsepower and 1645 lb-ft of peak torque, it will easily handle mountainous terrain even while towing a vehicle or boat.

Its XPI fuel system delivers a precise quantity of fuel at ultra-high pressures. This allows multiple injection events per cycle. This, in combination with enhanced turbocharging and reduced power demand from external engine components, results in high fuel efficiency along with quiet, smooth acceleration.

The ISX12 maintenance schedule features extended oil and oil filter changes, valve adjustments and fuel filter changes. Together with an increase in fuel economy of up to 2 percent over the previous model, this will lower total operating costs over the life of your motorhome.

Plus, when it’s time to trade up to a newer model, Cummins-powered motorhomes deliver traditionally higher resale value.

A Cummins-designed and manufactured aftertreatment system is fully integrated and now includes on-board diagnostics that continuously monitor engine and aftertreatment performance to ensure near-zero emissions.

Customizing the performance of your engine is possible through the use of Cummins PowerSpec, an online tool that lets you adjust operating parameters to match your need for enhanced fuel economy, higher performance or a balance between the two. See for details.

All of this is backed by unmatched support, from the largest service network in North America. This includes exclusive programs like Coach Care™ and 24/7/365 assistance from your Cummins Care representatives at 1-800-DIESELS (1-800-343-7357).

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

450-500 hp

335-373 kW

Peak Torque

1,550-1,645 lb-ft

2,102-2,230 N•m

Governed Speed

2,100 rpm

Clutch Engagement Torque

800 lb-ft

1,085 N•m

Number of Cylinders


Biodiesel Compatibility

Up to B20


System Weight (Dry)

2,880 lb

1,306 kg

Product Finder Specifications

Certification Level EPA 2013
Power 450 - 500 hp / 336 - 373 kW
Torque 1550 - 1645 lb-ft / 2102 - 2230 N•m


Engine Model 
Advertised Horsepower (kW) Peak Torque lb-ft (N•m) @ rpm Governed Speed
ISX12 500 500 (373) 1645 (2230) @ 1200 1800 rpm
ISX12 450 450 (336) 1550 (2102) @ 1200 1800 rpm


XPI Fuel System – Delivers superior performance at every speed. Multiple injection events per cycle improve fuel efficiency and enable smoother, quieter operation.

VGT™ Turbocharger From Cummins Turbo Technologies – The patented design is widely recognized as the industry leader for performance. Electric actuation provides quick throttle response and increased braking horsepower.

Cooled Exhaust Gas Recirculation (EGR) – The next-generation system lowers combustion temperatures, for reduced emissions and optimized fuel economy.

High-Capacity Electronic Control Module (ECM) – A single ECM manages the entire engine and aftertreatment system, for optimum performance and fuel economy. This ECM is used across the board for Cummins on-highway engines, to simplify servicing.

C Brake™ by Jacobs® – This optional engine braking system has been designed specifically for the ISX12, delivering up to 305 bhp, for greater vehicle control with reduced service brake wear.


Cummins Aftertreatment System From Cummins Emission Solutions – This proprietary system consists of a Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) technology, for near-zero emissions.

Fleetguard®Fuel Filters, Lube Filters And Diesel Exhaust Fluid (DEF) From Cummins Filtration – Fleetguard filters protect against corrosion and contaminants that can cause performance issues. High-quality DEF is readily available at all Cummins distributors, within Cummins Filtration’s vast North American distribution network and at major service stations and truck stops.


Duty Cycles

Miles/ Kilometers


Oil and Filter

25,000 mi / 40,000 km


Fuel Filter*

30,000 mi / 48,000 km


Coolant Filter*

50,000 mi / 80,000 km


Overhead Adjustment

250,000 mi / 400,000 km


Coalescing Filter

150,000 mi / 400,000 km


DEF Filter

300,000 mi / 480,000 km


Diesel Particulate Filter

200,000 mi / 320,000 km


*With appropriate filter

Brochures Available

Title Bulletin Number Request View  
ISX15 And ISX12 Engines For RV Applications Spec Sheet (2013) 4971465 Request View  Download
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
RV Applications Brochure (2013) 4971462 Request View  Download