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

Model 217, 222

Courtesy of MERCEDES-BENZ USA

Function requirements, general

No undervoltage or overvoltage

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 and exit function allows the driver to get in and out of the vehicle easily. For this purpose, the steering column is moved upward before the driver gets in or out of the vehicle. The steering column is adjusted and the current position of the steering column is stored by the driver seat control unit.

ELE encompasses the following subfunctions:

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

Normalizing

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.

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 (Model 222 with code 275 (Memory Package) or Model 217)
Retrieve stored position for steering column (Model 222 with code 275 (Memory Package) or Model 217)

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 (Model 222 with code 275 (Memory Package) or Model 217)

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 and release front left memory function switch for at least 100 ms, then press 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 data records 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.

Retrieve stored position for steering column (Model 222 with code 275 (Memory Package) or Model 217)

To move to a stored position, the corresponding 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 switches 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 seat control unit actuates the steering column adjustment motors directly.

Additional function requirements for steering column adjustment easy entry/exit

Easy entry and exit feature activated using COMAND controller unit or head unit
Driving position stored

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

Steering column adjustment easy entry and exit feature

The easy entry and exit function allows the driver to get in or out of the vehicle more easily. For this purpose, the steering column is moved upward before the driver gets in or out of the vehicle. The function of the easy entry and exit feature can be activated or deactivated using the vehicle settings menu in the COMAND controller unit or in the head unit.

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

Move to easy entry/exit position
Move to drive position
Repetition safeguard
Crash-active steering column adjustment

Move to easy entry/exit position

Movement to the entry/exit position is triggered in the case of the following status transitions:

Switch off circuit 15C
Opening of driver door with circuit 15C OFF
Opening of driver door with circuit 15C ON
Opening of driver door with circuit 15R 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 transmits the status of the driver door (open/closed) via interior CAN to the driver seat control unit. To define the position of the steering column, 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 current position of the steering column (driving position) and actuates the steering column up/down adjustment motor accordingly.

Move to drive position

The driver seat control unit actuates the steering column up/down adjustment motor under the following conditions in order to return the steering column to the driving position:

Closing driver door with circuit 15 On
Change from circuit 30 to circuit 15C with driver door closed
Change from circuit 15C to circuit 15R with driver door closed
Change from circuit 15R to circuit 15 ON with driver door closed

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

Manual adjustment request over the steering column adjustment switch
Memory setting request (model 222 with code 275 (Memory Package) or model 217)
Reversal of circuit 15 transition or driver door status change
Defect of steering column up/down Hall sensor

Repetition safeguard

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 when the left front door control unit sends the status of the driver door (open/closed).

Crash-active steering column adjustment

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 if the following occurs:

Driver door opened
Switch off circuit 15C

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 transmits the status of the driver door (open/closed) via 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.

	Electrical function schematic, steering column adjustment		PE46.15-P-2053-97SEA
	Electrical function schematic for steering column adjustment in conjunction with easy entry and exit feature		PE46.15-P-2055-97SEA
	Overview of system components, electric seats		GF91.29-P-9992LF