Transfer Box ECU The transfer box ECU is located behind the battery, on the bulkhead. The position of the ECU changes with LH and RH drive vehicles. The transfer box ECU is the main unit for controlling the operation of the transfer box. The ECU software was designed in conjunction with Land Rover, Siemens and New Venture Gear. The ECU is connected on the CAN bus and controls the transfer box operation using CAN messages from other ECU's on the network. The transfer box ECU uses three connectors for all inputs and outputs. The ECU receives one permanent power supply via a A fusible link located on the bulkhead, behind the battery, and an ignition supply via fuse 33 in the passenger compartment fusebox. A second feed via the ignition switch position I and fuse 37 in the passenger compartment fusebox, activates the neutral selection function. Refer to Operation - Neutral Selection for further details. The ECU memorises the position of the actuator when the ignition is switched off. When the ignition is subsequently switched on, the ECU powers the actuator until the lead screw drives the fork and rail assembly against the end stop for the previous range. The ECU then calibrates itself to this position and confirms that the selected range is correct. The ECU controls the closed loop position sensing system within the actuator and regulates the power supply to the motor to ensure the optimum shift quality is achieved. Using a series of specific software algorithms, the ECU is capable of adjusting the performance of the synchroniser system to produce smooth and effortless shifting, regardless of temperature and vehicle speed, providing the neutral and speed parameters are achieved. The ECU uses a series of programmed shift maps to control the synchronisation speed and ensure that a maximum shift time of 1.2 seconds is achieved. If the ECU is replaced, TestBook/T4 must be connected to the vehicle and the transfer box ECU self-calibration procedure must be performed. This procedure must also be performed if the actuator and gearbox assembly is replaced.