Electronic Function
| 1 | Oil pressure and temperature sensor | 3 | Control valve/axial solenoid |
| 2 | Differential electronic module (DEM) | 4 | Electrical feed pump. |
The differential electronic module (DEM) is secured directly to the coupling unit and forms a single unit with the control valve/axial solenoid. The differential electronic module (DEM) communicates, among other things, with the engine control module (ECM) and the brake control module (BCM) via the control area network (CAN). The differential electronic module (DEM) uses the sensor signals to control the oil pressure to the multi-plate clutch by adjusting the axial solenoid. The axial solenoid regulates the control valve constantly using a pulse width modulation (PWM) signal. The basic pressure is generated by the electronic feed pump. The oil pressure for the multi-plate clutch determines the amount of torque which can be transferred to the rear wheels.
Active On demand Coupling (AOC) has an oil pressure and temperature sensor, which gauge the prevailing temperature and pressure of the hydraulic fluid. The oil pressure and temperature sensor provide the differential electronic module (DEM) with information about the temperature and pressure. Four wheel drive is disengaged to protect the coupling unit from damage if the temperature becomes too high, above 105°C. The coupling unit is re-engaged at full function when the temperature falls below 101°C. To protect the drive shafts, constant velocity joints and to prevent overheating, the differential electronic module (DEM) has functions that slightly reduce torque transfer to the rear wheels in certain driving situations.
"Trailer detection" is an example of such a function. This functions works on the basis that if a trailer is connected to the vehicle and the driving conditions are such that the front wheels "grip" the surface, the differential electronic module (DEM) opts to transfer a smaller percentage of the total torque to the rear wheels, than it otherwise would have done without a trailer.
This results in the main percentage of torque being at the front wheels. Therefore, protecting the drive line from extreme load.