Diesel Exhaust Fluid Heater Control Unit - EU6 Engines Only
The Diesel Exhaust Fluid (DEF) heater control unit is located in the luggage compartment. The DEF heater control unit is located on a stud on the right rear wheel arch reinforcing panel and secured with a nut.
The DEF heater control unit receives a permanent 12V primary battery supply via fuses in the Battery Junction Box (BJB) and the Rear Junction Box (RJB). A second power supply is provided via the Powertrain Control Module (PCM) relay in the Engine Junction Box (EJB).
The DEF heater control unit provides current information for each heater power stage on a private Controller Area Network (CAN) bus to the PCM. Any faults detected are stored in the PCM fault memory and can be retrieved with an approved diagnostic system.
The DEF line heater receives a power supply from the DEF heater control unit. The DEF line heater provides heating of the DEF as it passes from the DEF tank to the DEF injector in cold conditions.
The heater element in the DEF tank module receives a power supply from the DEF heater control unit. The heater element provides heating of the DEF in the DEF tank.