Def Heater Control Unit

WARNING: This page is about a different car, the 2018 Jaguar XE and 2017 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The DEF heater control unit is located in the left side of the luggage compartment. The control unit is attached to the luggage compartment floor panel with one nut. The heater system enables rapid SCR system operation in the event of frozen DEF and ensures an adequate quantity of defrosted DEF is available at all operating points. The DEF heater control unit has a switched power supply from the Rear Junction Box (RJB), which is controlled by the PCM.

The DEF heater control unit has hardwired connections to the DEF tank module and the DEF line heater element. If the ambient air temperature is below -7 °C (19.4 °F), the PCM switches on the DEF heater control unit via the Private CAN bus. The DEF heater control unit energizes the heater elements, located in the DEF tank module and in the DEF line. The DEF heater control unit has on-board diagnostics to detect and report faults to the PCM via the Private CAN bus.