Diesel Exhaust Fluid (DEF)

To meet stringent 2010 calendar year emissions requirements, 2011 Ram Chassis Cabs with the Cummins® Turbo Diesel engine will be equipped with a Diesel Exhaust Fluid (DEF) injection system and a Selective Catalytic Reduction (SCR) catalyst. When needed, the DEF is injected into the exhaust to reduce NOx (Nitrous Oxide) emissions coming out of the tail pipe.

An advantage of this DEF system is that, unlike other manufacturers, the Cummins® Turbo Diesel engine will maintain full power when fluid is low. The tank holds eight gallons of DEF and is designed to be filled at oil change intervals, depending on duty cycle. DEF is available through Mopar® and the Chrysler Dealer Network, and through Cummins dealers and distributors.

The system includes the following components, all mounted away from upfit zones:

  • DEF tank, mounted under the cab
  • DEF filler, in the gap between the cab and upfitter body
  • DEF pump
  • DEF injector
  • DEF control module
  • NOx sensor
  • SCR catalyst

Learn More>


  • Diesel Exhaust Fluid (DEF)

    • DEF warning messages
      DEF warning messages

      To ensure that your vehicle does not run completely out of DEF, a series of warning messages will display when the fluid gets low, but before the tank is empty and the engine will no longer start. This series of warnings is intended to ensure your truck always meets emissions standards and give you ample time to refill the DEF. Some DEF will be left in the tank when the message "Refill DEF Engine Will Not Start" is displayed, and therefore the vehicle will still meet all emissions standards. The vehicle will operate with full performance throughout the low DEF warning cycle until the vehicle is shutoff and will no longer start.

      • "Low DEF Refill Soon" (1,000-600 miles left)
      • "Refill DEF Engine Will Not Restart in ___ Miles" (600-100 miles left)
      • "Refill DEF Engine Will Not Start" (100-0 miles left)
    • Programs & Incentives

      Programs & Incentives

      Purchase, accessorize & maintain
      a vehicle for your business.

      See how >
    • BusinessLink®


      Perks for business owners

      Get the advantage >
    • Body Builder's Guide

      Body Builder's Guide

      Safety & security, emissions
      and electrical data for upfitters.

      Get the specs >

    *MSRP excludes destination, taxes, title and registration fees. Starting at price refers to the base model, optional equipment not included. A more expensive model may be shown. Pricing and offers may change at any time without notification. To get full pricing details, see your dealer.
    The text, images, graphics, sound files, animation files, video files and their arrangement herein are all subject to Copyright and other intellectual property protection. These objects may not be copied for commercial use or distribution. Unless otherwise indicated, all marks displayed on Chrysler Group LLC Internet sites are subject to the trademark rights of Chrysler Group LLC, including each of Chrysler Group LLC's primary brands (Chrysler, Dodge, Jeep«, Ram, and Mopar), its model nameplates, and its corporate logos and emblems.