Electronic Differential Control Unit, Component Description - GF28.19-P-3221VGG
Model 463 with transmission 725.0
as of model year 2019
Shown on electronic differential control unit (N3/2)
Location
The electronic differential control unit is mounted in the area of the center console.
Task
The electronic differential control unit actuates the interaxle differential lock and the differential locks in the front axle and rear axle.
The electronic differential control unit actuates the all-wheel drive actuator (N45m1) through the user interface CAN (CAN HMI), electronic ignition lock control unit (N73), suspension FlexRay (Flex E) and the all-wheel drive control unit (N45) as well as the front axle differential lock actuator (M46/7) and rear axle differential lock actuator (M46/8) over the differential locks LIN (LIN AGGS). The all-wheel drive control unit and the front axle and rear axle differential lock actuators report back to the electronic differential control unit whether the interaxle differential lock or the differential locks are engaged.
The electronic differential control unit is equipped with three switches. These switches actuate the respective interaxle differential lock in the transfer case, and the differential lock for the front axle and the rear axle. The engagement indicator (yellow) is located below the respective switch. After pressing the switch, the engagement indicators light up first if all the requirements for switching on the differential locks or the interaxle differential locks on the front axle or rear axle are fulfilled. The function indicators (red) are located above the respective switch. The function indicators go on as soon as the interaxle differential lock/the differential locks are active.
The locks can only be activated in the following sequence:
- Interaxle lock
- Rear axle differential lock
- Front axle differential lock
The sequence number for activation of the lock is noted on the respective switch.
The interaxle differential lock and the differential locks on the front axle and rear axle can be deactivated again by operating the respective switch. The locks are deactivated in reverse order, starting with the front axle differential lock then the rear axle interaxle differential lock. If a switch with higher priority is operated by the driver (e.g. interaxle differential lock), when locks with lower priority are still active (differential lock on front axle and rear axle), the locks with lower priority are automatically deactivated.
The function indicator lamps remain on after the switches have been actuated until the respective lock is mechanically deactivated.
Messages in the instrument cluster (A1)
If case of faults in the system, messages to this effect will be displayed in the instrument cluster. If the differential lock or the interaxle differential lock is engaged, it is shown on the instrument cluster.
The instrument cluster displays a G, when the transfer case is in the LOW RANGE off-road gear or where at least one lock is switched on.
Under certain circumstances, the driver assistance systems will not be available when the locks are engaged.
Control module programming
The electronic differential control unit can be programmed, i.e., the complete control unit software can be exchanged (replaced). The software required for control unit programming is stored on the diagnosis software DVD.
User interface CAN
The electronic differential control unit is connected to the vehicle's networking group via the user interface CAN and exchanges data with other control units.
| Input factors over a direct line | Output factors over the AGGS LIN | Supplemental information |
|---|---|---|
| Terminal 15 | - | - |
| Circuit 30 | - | - |
| Circuit 31 | - | - |
| - | Front axle differential lock actuator (M46/7) | - |
| - | Rear axle differential lock actuator (M46/8) | - |
User interface CAN input/output signals
Input and output factors of the following control units are sent or received by the electronic differential control unit over the user interface CAN:
| Input factors over user interface CAN (CAN HMI) | Output factors over user interface CAN (CAN HMI) | Supplemental information |
|---|---|---|
| - | Instrument cluster (A1) | - |
| All-wheel drive control unit (N45) | All-wheel drive control unit (N45) | Over the suspension FlexRay (Flex E) and the electronic ignition lock control unit (N73) |
| Electronic Stability Program control unit (N30/4) | Electronic Stability Program control unit (N30/4) | Over the suspension FlexRay (Flex E) and the electronic ignition lock control unit (N73) |
| - | Electrical power steering control unit (N68) | Over the suspension FlexRay (Flex E) and the electronic ignition lock control unit (N73) |
| Electronic ignition lock control unit (N73) | Electronic ignition lock control unit (N73) | - |
| Powertrain control unit (N127) | Powertrain control unit (N127) | Over the suspension FlexRay (Flex E) and the electronic ignition lock control unit (N73) |