Electric steering column calibration

Electrical steering column calibration

The electrical steering column calibration enables the driver to set the optimized position of the steering wheel. There is a switch on the left of the steering column for operation. The inclination and length of the steering column are adjusted electrically. The control for the electrical steering column is located in the IHKA control module.

Brief description of components

The following components are described for the electrical steering column calibration:

Switch for steering column calibration

The driver can use this switch to adjust the inclination and length of the steering column. The switch for the steering column calibration is on the left of the steering column.

Steering column calibration unit

The steering column calibration unit is a composite component and contains a number of components. The integrated components are:

Steering column calibration motor
Solenoid
Hall sensor on the steering column calibration motor
Hall sensors for Softstop

Index	Explanation	Index	Explanation
1	Steering column calibration unit	2	Connector for steering column calibration unit
3	Steering column calibration motor

Steering column calibration motor

The steering column calibration motor adjusts the angle and length of the steering column.

Solenoid

The solenoid changes the calibration direction as regards length and angle.

Hall sensor on the steering column calibration motor

The Hall sensor on the steering column calibration motor passes on a signal to the IHKA control module on calibration of the steering column. The IHKA control module then determines the position of the steering column.

Hall sensors for Softstop

The Hall sensors for the Softstop detect when the steering column is approaching the limit position.

Driver's door contact

The IHKA control module requires the signal from the door contact. In conjunction with the terminal status, the signal for Easy Entry / Easy Exit is used.

Signal path: Door contact driver's door -> Footwell module (FRM) -> K-CAN -> IHKA control module

The following control modules are involved in the electrical steering column calibration:

IHKA: Control module

The IHKA control module activates the electrical steering column calibration. The IHKA control module is supplied with voltage via terminal 30 G (with 20 A fuse). The IHKA control module is activated via the wake-up line (terminal 15). The positions for the steering column memory are also saved in the IHKA control module.

Index	Explanation	Index	Explanation
1	Back of control module	2	Connector for steering column calibration unit

System functions

The following system functions are described for the electrical steering column calibration:

Steering column calibration
Steering column memory
Overheating protection for the steering column calibration motor

Steering column calibration

The driver can use a switch to adjust the steering column.

Index	Explanation	Index	Explanation
1	Switch for steering column calibration	2	Calibration directions

The electrical steering column calibration has a Softstop for the axial and vertical axis. When the end of the axle approaches the Hall sensors for the Softstops, activation of the steering column is stopped. If the Hall sensors for the Softstops were defective, the steering column calibration motor would encounter blocking current on reaching the end position and would be switched off.

Steering column memory

The position of the steering column is picked up by the Hall sensor directly at the electric motor. The position is then sent to the IHKA control module and saved in the IHKA control module. For the key memory, this means that the position of the steering column can be called up for all ignition keys.

To support entry and exit, the inclination calibration moves to the highest position.

For Easy Exit, the steering column calibration is automatically activated under the following conditions:

Terminal R OFF
Terminal R On and driver's door is opened (via door contact)
Terminal 15 Off with opened driver's door (via door contact)

The steering column memory is activated under the following conditions:

One of the two memory buttons for the seat memory and the steering column memory on the seat is pressed (as of terminal R Off).
Another identification sensor is used (personalization). Condition: in the Central Information Display (CID) the selection ”Last seat position after unlocking” is activated in the ”Settings” menu.

In both cases, the steering column memory only moves to the corresponding memory position after terminal 15 On.

Notes for Service department

Diagnosis instructions

After coding or programming the IHKA control module, standardization of the steering column is to be run. After repair work on the electrical steering column calibration, the service function ”Standardization” is also to be run.

Note! Failure of the Hall sensor on the motor

In the event of failure of the Hall sensor, no identification of the position is possible for the steering column calibration. In the same way, the system cannot move to any position saved in the memory. The Softstop is switched off. The time for activation of the overload protection is shortened. This protects the steering column calibration motor against overheating.

Note! Failure of the Hall sensors for the Softstops

In the event of failure of the Hall sensors for the Softstops, the time for activation of the overload protection is shortened. This protects the steering column calibration motor against overheating.

Note! System state due to cold

Blocking of the steering column calibration due to cold is regarded as a mechanical stop. This might mean that the adjusting path in one calibration direction is restricted.

Notes on coding / programming

Important! IHKA control module

After coding or programming the IHKA control module, standardization of the steering column is to be run.

No liability can be accepted for printing or other faults. Subject to changes of a technical nature