GF91.29-P-0004SC Electric Seat Adjustment (ESA) Function
GF91.29-P-0004SC Electric Seat Adjustment (ESA) Function
The following changes can be performed manually on the front seats:
^ Head restraint adjustment (A)
^ Backrest adjustment (B)
^ Seat height adjustment (C)
^ Seat fore/aft adjustment (D)
^ Seat cushion fore/aft adjustment (E)
^ Seat cushion inclination adjustment (F) In addition, the following functions are implemented:
^ Save/call up seat position
^ Easy entry/exit (driver seat)
^ Easy entry (rear easy entry)
^ Front passenger head restraint unoccupied position (not (United States Of America), up to 31.5.07)
^ Head restraint presetting (not Economic Commission for Europe (ECE))
Component Identification:
Function requirements
^ Circuit 15R On or respective vehicle door open (up to 31.5.07)
Manual adjustment
Adjustment of front seats is performed using the respective seat operation switch group. The adjustment request is read in over the front door LIN by the respective door control unit, which then directly actuates the corresponding motors.
If several adjustment requests are pending at the same time, the motors, which are split up into 2 groups, are actuated as follows (only one motor can be active per group):
^ Group 1
- Longitudinal adjustment (high priority)
- Inclination adjustment (high priority)
- Depth adjustment (low priority)
^ Group 2
- Backrest adjustment (high priority)
- Height adjustment (high priority)
- Head restraint adjustment (low priority)
The driver can also use the seat operation switch group to adjust the front passenger seat. After actuating the left or right seat adjustment selection switch (S22s10), the front passenger seat adjustment is active for 10 s and this is indicated by the light emitting diode (LED) in the seat adjustment selection switch.
Store seat position
Three different seat settings can be stored for each of the front seats using the seat operation switch group. There are two possibilities to store the data:
^ Press and hold memory switch (S22s6 or S23s6), at the same time briefly press memory 1 switch (S22s7 or S23s7), memory 2 switch (S22s8 or S23s8), memory 3 switch (S22s9 or S23s9) or
^ press the memory switch for at least 40 ms and press the respective memory switch within 3 s.
The seat settings are stored in the respective seat control unit.
On the driver side, the instantaneous position of the steering column and outside mirrors are additionally stored.
Automatic storing
When switching off the engine (circuit 15C) with the driver door closed, the current setting for the driver seat and the position of the steering column and outside mirrors are automatically stored (last driving position).
Call up seat position
To call up a stored seat position, the corresponding memory switch in the seat operation switch group must be pressed and held until the stored seat setting has been reached. If the button is released, the adjustment procedure is terminated.
The adjustment request is read in over the front door LIN from the door control unit and forwarded over the Interior CAN to the seat control unit. The seat control unit then directly actuates the corresponding motors.
At the same time on the driver-side, as the stored seat position is moved to, the steering column and the outside mirrors move to their assigned stored positions.
Synchronizing
Normalization refers to the assignment between the absolute adjustment position and the position recorded by the seat control unit. Normalization must be performed during initial startup or in a denormalized condition.
The system has to move to the following positions:
^ Longitudinal adjustment to the front stop
^ Angle adjustment to the up-stop
^ Height adjustment to the up-stop
^ Depth adjustment to the rear stop
^ Backrest adjustment to the front stop
^ Head restraint adjustment to the lower stop
To do so, press switch (S22s1, S22s2, S22s3, S22s5, S23s1, S23s2, S23s3 or S23s5) in the seat operation switch group until the respective mechanical stop is reached and hold it pressed for another 0.25 s.
Upon successful normalization, the seat control unit switches off the respective motor.
Denormalization
An adjustment is denormalized:
^ when a mechanical stop is exceeded or
^ when the waiting time of at least 5 s after a seat adjustment until battery voltage has been disconnected is not observed or
^ when a Hall sensor of the motors is recognized as defective
Easy entry (rear easy entry)
Function requirements
^ Front seat normalized
^ Easy entry/exit inactive (for driver seat)
Moving to entry position
When pulling the backrest release handle, the current seat position is stored automatically as initial position. The head restraint then moves to the lower stop to avoid any collisions with the headliner. Folding the backrest forward out of the reclining position actuates the backrest angle microswitch and this in turn then initiates the longitudinal movement of the seat towards the front.
The backrest is mechanically locked in the folded forward position.
After reaching the end position, the longitudinal movement of the seat is stopped and the backrest adjusted, if necessary.
If the backrest was set to a relatively "flat" position, it is adjusted forward to increase the entry area and to ensure that the rear passenger's legs are not trapped when it is folded back.
If the backrest was set to a relatively "steep" position, it is moved backwards to enable it to be locked in the folded forward position.
Moving to initial position
Pulling the backrest release handle mechanically releases the backrest again, which can then be folded backward. The backrest angle microswitch closes and the seat adopts the previously stored position. The backrest is mechanically locked again in the folded back position.
The excess force limiter is active when the seat is moving backward. If any obstruction is detected, the front seat moves forward again.
Play protection
Adjustment of the front seat without reaching the end position induced by folding the backrest back and forth alternately is limited to three times.
It can then only be actuated again after locking and unlocking the central locking system (CL).
Driver and front passenger seat head restraint presetting (not ECE)
The height of the head restraints is automatically preset by the seat control unit depending on the longitudinal adjustment of the front seats.
The head restraint presetting function can be switched on and off using STAR DIAGNOSIS.
Front passenger head restraint unoccupied position (not (United States Of America), up to 31.5.07)
The front passenger seat occupancy status is transmitted by the restraint systems control unit over the central gateway control unit to the seat control unit. If the front passenger seat is not occupied, the seat control unit adjusts the head restraint to the lowest position.
Easy entry/exit feature
Function requirements
^ Driver seat normalized
^ Backrest locked in drive position
Function
The entry/exit position for the driver seat lies 60 mm behind the drive position. Driver seat fore/aft adjustment is only possible up to 190 mm behind the front stop. If the remaining adjustment distance is < 30 mm, no adjustment is performed (up to 31.05.07).
In vehicles as of 1.6.07 the value is no longer defined at 190 mm, but varies depending on the height of the seat.
Adjustment to the entry/exit position is triggered for the following status transitions:
^ Circuit 15C ON -> Circuit 15C OFF
^ Driver door closed -> Driver door open (with circuit 15R On)
^ Driver door closed -> Driver door open (with circuit 15C On)
Adjustment to the drive position is triggered for the following status transitions:
^ Circuit 15C OFF -> Circuit 15C On (driver door closed)
^ Circuit 15C ON -> Circuit 15R On (driver door closed)
^ Circuit 15R ON -> Circuit 15 On (driver door closed)
^ Driver door open -> Driver door closed (with circuit 15 On)
Easy entry/exit repeat limiter
Repeatedly inserting and removing the transmitter key may cause the equipment to move between the easy entry/exit position and the driving position every time.
In order to avoid this, the number is limited to 5 cycles. The counter is reset when the transmitter key is turned to circuit 15R On" or the status of the driver door is changed.
Anti-lock device
The anti-lock function is realized by Hall sensors in the motors, the signals of which are evaluated by the seat control unit.
If a Hall sensor is faulty, actuation of the respective motor is aborted after 2 s. Adjustment is then only performed if a request is sent after 2 s. Adjustment in the opposite direction is possible straight away.
