Electric Steering Column Adjustment (ELE), Function - GF46.15-P-0004FR

Model 257, 290 

up to model year 2021 

with code 275 (Memory Package (driver's seat, steering column and mirror)) 

Courtesy of MERCEDES-BENZ USA

Electric steering column adjustment - general 

The adjust/store steering column function allows the steering column to be adjusted to various different positions and these positions to be stored. The easy entry/exit function allows the driver to get in and out of the vehicle easily. In the process the steering column is moved upwards before getting in or out. The steering column is adjusted and the current position of the steering column is stored by the driver seat control unit.

The electric steering column adjustment function comprises the following subfunctions:

• Normalize steering column 
• Adjust/save steering column 
• Steering column adjustment easy entry and exit feature 

Normalize steering column 

Normalization is the basis for assignment of the current position to the steering column position detected by the driver's seat control unit. Normalization must be performed during initial startup or in a denormalized condition. For this purpose, the front and top mechanical end stop must be approached. During initial startup, normalization is performed using the diagnostic tester. After denormalization, normalization can be performed using the adjustment function. To do so, press and hold the steering column adjustment switch after reaching the mechanical end stops for another 250 ms.

The steering column tube module control unit reads in the switch position of the steering column adjustment switch directly and sends it over the suspension FlexRay, the electronic ignition lock control unit and interior CAN to the driver seat control unit. The driver seat control unit directly actuates the corresponding steering column adjustment motor, reads in the signals directly from the respective steering column Hall sensor and evaluates these signals. Upon successful normalization, the driver's seat control unit switches off the corresponding steering column adjustment motor. Through the process of normalization, a location counter in the driver's seat control unit is set to zero.

During steering column adjustments, the driver seat control unit defines the adjustment range of the steering column by counting the Hall sensor signals.

Additional function requirements for adjust/store steering column 

• Steering column normalized

Adjust/save steering column 

The adjust/store steering column function allows the steering column to be adjusted to various different positions and these positions to be stored.

The adjust/store steering column function includes the following subfunctions:

• Adjust steering column 
• Save position of steering column 
• Call up stored position of steering column 

Adjust steering column 

The steering column is adjusted by operating the steering column adjustment switch. The steering column tube module control unit reads in the switch position of the steering column adjustment switch directly and sends it over the suspension FlexRay, the electronic ignition lock control unit and interior CAN to the driver seat control unit. The driver seat control unit directly actuates the corresponding steering column adjustment motor, reads in the signals directly from the respective steering column Hall sensor and evaluates these signals. Actuation continues for as long as the steering column adjustment switch is pressed or until an end position is reached.

Save position of steering column 

The current position of the steering column can be stored together with the position of the driver seat and the outside mirrors. Saving occurs using the left front seat adjustment switch group.

The following possibilities exist to do this:

• Press and hold down the left front memory function switch, then press the corresponding front left memory switch.
• Press left front memory function switch for more than 100 ms and then release, then press the corresponding front left memory switch within 0.2 to 3 s.

The left front door control unit reads in the status of the corresponding switches in the left front seat adjustment switch group over the left front door LIN and sends the "Store memory position" request over the interior CAN to the driver seat control unit. The driver's seat control unit uses the signals from the steering column Hall sensors to save the current position of the steering column. Up to three different positions can be stored. When the position of the steering column has been successfully stored, an acknowledgment tone is output by the instrument cluster speaker. The driver seat control unit sends the request for this via the interior CAN, electronic ignition lock control unit and user interface CAN to the instrument cluster which directly actuates the instrument cluster speaker.

Call up stored position of steering column 

To call up a stored position, the corresponding left front memory switch must be pressed and held down until the steering column has reached the stored position. Releasing the switch causes the adjustment procedure to be aborted immediately.

The left front door control unit reads in the status of the corresponding memory switch in the left front seat adjustment switch group via the left front door LIN and sends the "Adopt memory position" request via the interior CAN to the driver seat control unit. The driver's seat control unit then actuates the steering column adjustment motors for as long as the stored position of the steering column is reached.

Additional function requirements for steering column adjustment easy entry/exit 

• Steering column normalized
• Easy entry/exit function activated via head unit
• Driving position stored

The head unit sends the status of the easy entry/exit function via the user interface CAN, electronic ignition lock control unit and interior CAN to the driver seat control unit.

Steering column adjustment easy entry and exit feature 

The easy entry/exit function allows the driver to get in and out of the vehicle easily. In the process the steering column is moved upwards before getting in or out. The easy entry/exit function can be activated or deactivated via the head unit in the "Vehicle settings" menu.

The steering column adjustment easy entry/exit function comprises the following subfunctions:

• Move to easy entry/exit position 
• Move to drive position 
• Activate repeat limiter 
• Activate crash responsive exit aid 

Move to easy entry/exit position 

Movement to the entry/exit position is triggered under the following conditions:

• Switching off of circuit 15 when the driver's door is open
• Driver door opened with circuit 15 OFF

The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the driver's seat control unit. The left front door control unit detects the status of the driver door and sends the status via the interior CAN to the driver seat control unit. To define the current position of the steering column (driving position), the signals from the steering column up/down Hall sensor are read in directly and evaluated by the driver seat control unit. The driver seat control unit reads in all relevant information, stores the driving position and actuates the steering column up/down adjustment motor accordingly.

Move to drive position 

Movement to the driving position is triggered in the case of the following status transitions:

• Switch-on of circuit 15 with driver door closed
• Closing driver door with circuit 15 On

The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the driver's seat control unit. The left front door control unit detects the status of the driver door and sends the status via the interior CAN to the driver seat control unit. The driver's seat control unit reads in all relevant information and actuates the steering column up/down adjustment motor according to the stored data.

The "Move to entry/exit position" or "Move to driving position" functions are aborted under the following conditions:

• Undervoltage or overvoltage
• Manual adjustment request over the steering column adjustment switch
• Memory adjustment request
• Reversal of circuit 15 transition or driver door status change
• Defect of steering column up/down Hall sensor Activate repeat limiter 

In order to prevent the steering column up/down adjustment motor from overloading in the case of repeated switching on/off of the "Move to entry/exit position" and "Move to driving position" functions, the number of adjustment cycles is limited to five only. This is reset as soon as the electronic ignition lock control unit sends the status of circuit 15R or if the left front door control unit sends the "Driver door open" or "Driver door closed" status.

Activate crash responsive exit aid 

To make it easier for the driver to exit the vehicle or for first aiders to remove the driver from the vehicle after an accident, the steering column is automatically adjusted upward to a predefined position following a crash event when the driver door is opened.

The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the driver's seat control unit. The left front door control unit detects the status of the driver door and sends the status via the interior CAN to the driver seat control unit. The Supplemental Restraint System control unit sends the crash signal via user interface CAN, electronic ignition lock control unit and interior CAN to the driver seat control unit. The driver's seat control unit then directly actuates the steering column up/down adjustment motor.

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