Rear Axle Steering Control Unit, Basic Function - GF46.80-P-9890A

Model all (CAR) 

Example illustration, rear axle steering control unit 

Overview 

This document contains information on:

• General 
• Function 
  • Reading in of signals 
  • Evaluation of input signals 
  • Actuation of components 
  • Output of signals 

General 

The rear axle steering control unit uses various input signals to calculate the optimum steering angle of the rear wheels for the respective driving situation. To transfer the mechanical movements, the output signals of the rear axle steering control unit control the integrated electric motor.

Depending on the version of the steering on the rear axle, there is one central or two control units located on the wheel for implementing the rear axle steering function.

Models	Rear axle steering control unit (1)	Right rear axle steering control unit (2)	Left rear axle steering control unit (3)
206/254	X	-	-
223/295/296/297	X	-	-
232/290	-	X	X

Function 

Reading in of signals

The rear axle steering control unit also receives the following input signals:

• Status of circuit 15
• Drive system status
• Vehicle speed
• Control status of rear axle steering request
• Toe angle change request
• Rear axle steering tie rod force request
• Status of steering wheel angle sensor
• Status of roller dynamometer mode
• Snow chain mode status
• Accelerator pedal position status
• Drive position status
• Trailer hitch status

Evaluation of input signals

The received input signals are evaluated by the microprocessor integrated in the rear axle steering control unit. The corresponding component parts are actuated after evaluation of the input signals.

Actuation of components

The rear axle steering control unit actuates the integrated actuator motor directly.

Output of signals (vehicle with left and right rear axle steering control unit)

The rear axle steering control unit primarily transmits the following output signals:

• Rear axle steering actuator status
• Toe angle change request (master control unit to slave control unit)
• Rear axle steering display request

Output of signals (vehicle with central rear axle steering control unit) 

The rear axle steering control unit primarily transmits the following output signals:

• Rear axle steering actuator status
• Rear axle steering angle status

	Component descriptions
	Rear axle steering control unit, component description	Model 223	GF46.80-P-1001A
		Model 206	GF46.80-P-1001C
		Model 297	GF46.80-P-1001D
		Model 295	GF46.80-P-1001E