Automatically Controlled All-Wheel Drive (4MATIC), Function - GF28.00-P-0001FH
Model 238
Up To Model Year 2021
with code M005 (Vehicles with 4MATIC/all-wheel drive)
Automatically-controlled all-wheel drive (4MATIC) in general
The automatically regulated all-wheel drive is a permanent all-wheel drive with interaxle differential. All-wheel drive has advantages not only off-road, but also on roads providing good grip. The driving power is distributed to all the wheels. This results in greater traction and higher lateral stability at the driven wheels. The basic locking torque is 40 to 50 Nm and it helps to provide better traction at low engine torque.
Variable drive torque distribution (model 238.361/461)
For model 238.361/461 the drive torque is distributed variably to the front and rear axles.
The all-wheel drive control unit evaluates various information that exerts an influence on drive torque distribution, and matches it accordingly. This includes information that enables conclusions to be drawn about the surface being drive on and the given driving situation. The Electronic Stability Program control unit sends information about the wheel speeds, status and activities of the brake and traction system over the suspension FlexRay to the all-wheel drive control unit. The ME-SFI [ME] control unit sends information about the engine speed and engine torque over the engine CAN, powertrain control unit and the suspension FlexRay to the all-wheel drive control unit. The fully integrated transmission control unit sends information about the transmission status over the drive CAN, powertrain control unit and the suspension FlexRay to the all-wheel drive control unit.
The steering column tube module control unit sends information about the steering wheel angle and steering angle rate of change over the suspension FlexRay to the all-wheel drive control unit.
The AIR BODY CONTROL control unit sends information about the vehicle level over the suspension FlexRay to the all-wheel drive control unit.
The electrical power steering control unit sends information about the wheel angle over the suspension FlexRay to the all-wheel drive control unit.
The all-wheel drive control unit evaluates all incoming information and actuates the drive torque distribution over the all-wheel drive actuator. The all-wheel drive actuator operates the multiplate clutch thereby changing the drive torque distribution to the front and rear axle. The all-wheel drive control unit sends information about the drive torque distribution and the system status over the suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster. The instrument cluster displays this information.
Shown on variable drive torque distribution (model 238.361/461)
The drive train encompasses the following major assemblies, whose function is described in separate documents:
- 4MATIC transfer case, function
- Front axle transmission output 4MATIC function
- Oil supply for 4MATIC transfer case function
- 4MATIC front axle transmission, function
| 4MATIC transfer case, function | GF28.10-P-1000FH | ||
| 4MATIC front axle transmission output, function | GF28.10-P-1012FH | ||
| Oil supply for 4MATIC transfer case function | GF28.55-P-3010FH | ||
| 4MATIC front axle transmission, function | GF33.10-P-3000FH |