All DEF systems require heating elements to prevent DEF fluid from freezing at temperatures less than 12 degrees Fahrenheit. DEF Heating Pots are designed to quickly return DEF to liquid form, ensuring proper flow through the lines and pump unit. If your diesel vehicle is operating in limp mode, or is not operating at full power, a common culprit is a failed DEF heating element. CARDONE DEF Heater Pots include all necessary gaskets and O-rings needed for a complete replacement, and are quality tested to ensure trouble free installation, performance, and durability.