Steering Column Control Module: Description and Operation

GF54.21-P-6051RD Component Description For Steering Column Tube Module Control Unit
MODEL 172.4





N80 Steering column module control unit

Location
The steering column tube module control unit is located directly beneath the multifunction steering wheel (MFL) on the steering column tube of the steering column.

Task
The steering column tube module control unit controls the data exchange between the controls on the MFL and the steering column with the corresponding control units that implement the functions.
The steering column tube module control unit has the following tasks:
^ Reading in of sensors and signals
^ Evaluating input factors
^ Actuating components

Reading in of sensors and signals
The input factors are read in via the following connections:
^ Direct line
^ Steering LIN (LIN E1)
^ Chassis CAN (CAN E)

Direct line
The signals from the following components are read via a direct line:
- Steering wheel angle sensor (N49)
- Combination switch (S4)
- Turn signal lamps switch (S4s1)
- Headlamp flasher and high beams switch (S4s2)
- Low beam switch (S4s3)
- Windshield washer system switch (S4s4)
- Wipe switch (S4s5)
- CRUISE CONTROL lever (S40/4)
- Resume from memory switch (S40/4s1)
- Decelerate and set switch (S40/4s2)
- Accelerate and set switch (S40/4s3)
- OFF switch (S40/4s4)
- Indicator switch (S40/4s5)
- SPEEDTRONIC switch (S40/4s6) (not with code (494) USA version and not with code (498) Japan version)
- DISTRONIC control (S40/4r1) (with code (233) DISTRONIC PLUS)
- Steering column adjustment switch (S59)

Steering LIN
The steering wheel electronics (N135) directly reads in the signals for the following components and sends them over the steering LIN to the steering column tube module control unit:
- Left multifunction steering wheel button group (S110)
- Steering wheel downshift button (S110/1) (with code (428) steering wheel shift buttons)
- Right multifunction steering wheel button group (S111)
- Steering wheel upshift button (S111/1) (with code (428) steering wheel shift buttons)

Chassis CAN
The signals are imported by the steering column tube module control unit via the chassis CAN.
The functions resulting therefrom are described in the corresponding function descriptions (see block diagram or function schematic).

Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the affected components are then actuated.

Actuating components
Components are actuated via the following lines:
^ Steering LIN
^ Direct line

Steering LIN
The steering wheel electronics then actuates the following components directly, the signals for this are received by it through the steering LIN from the steering column tube module control unit:
- Symbol illumination of the multifunction steering wheel button groups

Direct line
The following components are actuated via a direct line:
- SPEEDTRONIC LED (S40/4v1) (not with code (494) USA version and not with code (498) Japan version)
The following components are actuated directly through a looped line by the Supplemental Restraint System control unit (N2/10):
- Driver airbag squib 1 (R12/13)
- Driver airbag squib 2 (R12/14)