Electric Steering Column Adjustment (ELE), Function - GF46.15-P-0004RF
Model 205, 253
with code 275 (Memory Package (driver's seat, steering column and mirror))
Function requirements general
- Steering column normalized
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 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 electric steering column adjustment function comprises the following subfunctions:
- Function sequence for normalization
- Function sequence for adjusting/saving steering column
- Function sequence for steering column adjustment 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 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.
Function sequence for adjusting/saving 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 function sequence
- Function sequence for save position of steering column
- Function sequence for call up saved steering column position
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 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.
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 t ≥ 0.2 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 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.
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 steering column adjustment easy entry/exit
- 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.
Function sequence for steering column adjustment 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 via the head unit in the "Vehicle 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 easy exit feature
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 reads in the status of the left front door rotary tumbler switch in the left front door lock directly and sends this status via the interior CAN to the driver's 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 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 reads in the status of the left front door rotary tumbler switch in the left front door lock directly and sends this status via the interior CAN to the driver's 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
Function sequence for 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.
Function sequence for crash-active easy exit feature
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 reads in the status of the left front door rotary tumbler switch in the left front door lock directly and sends this status via the interior CAN to the driver's 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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