Electrically Adjustable Steering Column (ESC), Function - GF46.15-P-0003GR

MODEL 166 up to model year 2016 with CODE 275 (Memory package (driver seat, steering column, mirrors))

Function requirements, general

No overvoltage or undervoltage

Electrically adjustable steering column (ESC), 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 makes it possible for 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 ESC [EVL] function comprises the following subfunctions:

Function sequence for normalization
Adjust steering column function sequence
Function sequence for save position of steering column
Function sequence for call up saved steering column position
Function sequence for easy entry/exit

Function sequence for normalization

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 this, the steering column adjustment switch must be pressed and held for t = 250 ms after each mechanical end stop has been reached.

The steering column tube module control unit reads in the switch position of the steering column adjustment switch directly and sends it via chassis CAN 1, 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 steering column function sequence

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 via chassis CAN 1, 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 stop is reached.

Function sequence for save position of steering column

The current position of the steering column can be saved 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 the left front memory function switch for t > 100 ms and release, then press the corresponding left front memory switch within t0.2 s 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 via the left front door LIN and sends the "Store memory position" request via 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. The request for this is sent by the driver seat control unit over interior CAN to the instrument cluster.

Function sequence for call up saved steering column position

To call up 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 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 easy entry/exit

Easy entry/exit function activated via instrument cluster
Driving position stored

The instrument cluster sends the status of the easy entry/exit function to the driver seat control unit via interior CAN.

Function sequence for easy entry/exit

The easy entry/exit function makes it possible for 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 using the instrument cluster in the "Settings" menu.

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

Function sequence for move to easy entry/exit position
Function sequence for "Move to driving position"
Function sequence for repeat limiter
Function sequence for crash-active steering column adjustment

Function sequence for 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 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.

Function sequence for "Move to driving position"

The driving position of the steering column is adjusted when the following status transitions occur:

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:

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

Function sequence for repeat limiter

Alternately switching circuit 15C on and off results in an alternating cycle between moving to the easy entry/exit position and the driving position. In order to prevent overload of the steering column adjustment motor high and low, the number of adjustment cycles is limited to five only. This s reset as soon as the electronic ignition lock control unit sends the circuit 15R status or when the left front door control unit sends a change in the door status.

Function sequence for 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, following a crash event the steering column is automatically moved upward to a predefined position 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 transmits the crash signal via chassis CAN 1, 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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	Electrical function schematic for steering column easy entry/exit adjustment		PE46.15-P-2051-97NAA
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