Electrical Seat Adjustment (ESA) - GF91.29-P-0009FRA
Model 257, 290 up to Model year 2021 with code 278 (Fully electric front seats) except code 275 (Memory Package (driver's seat, steering column and mirror))
Function requirements, general
- No overvoltage or undervoltage
Electrical seat adjustment (ESA), general
The ESA enables the electrical adjustment of the driver and front passenger seat.
The driver and front passenger seat can be adjusted as follows:
- Seat longitudinal direction
- Backrest inclination
- Seat height
- Seat inclination
The ESA function comprises the following subfunctions:
- Manual front seat adjustment
- Front passenger seat manual adjustment from driver's seat
- Antilock device
Manual front seat adjustment
The front seats are manually adjusted using the respective front switch group, seat adjustment. Operation of the front switch group, seat adjustment is read in over each front door LIN by the respective front door control unit. The respective front door control unit sends the adjustment requests over the interior CAN to the driver seat control unit or to the front passenger seat control unit. To adjust, hold down the switches in the front switch group, seat adjustment until the desired position is reached.
The driver seat control unit or the front passenger seat control unit actuates the following seat adjustment motors directly depending on the request:
- Seat adjustment motor, seat fore/aft adjustment
- Seat adjustment motor, backrest inclination
- Seat adjustment motor for seat inclination adjustment
- Seat adjustment motor for seat height adjustment
Front passenger seat manual adjustment from driver's seat
Operating the left or right seat adjustment switch in the left front seat climate control switch group enables you to activate the front passenger seat adjustment function. The front passenger seat can be manually adjusted 10 seconds. If an adjustment is made during this period, the front passenger seat adjustment remains active after the adjustment for another 10 seconds. After 10 seconds have passed without an adjustment being made, or another press of the left or right seat adjustment switch, the driver's seat can then be adjusted again.
The left front door control unit reads in the status of the left or right seat adjustment switch over the left front door LIN, and sends the "Front passenger seat adjustment active" signal over the interior CAN to the driver's seat control unit and to the front passenger seat control unit.
To adjust, hold down the switches in the left front switch group, seat adjustment until the desired position is reached. The left front door control unit reads in the status of the left front switch group, seat adjustment over the left front door LIN, and sends the adjustment requests over the interior CAN to the front passenger seat control unit. The front passenger seat control unit directly actuates the corresponding seat adjustment motors to match the request.
All adjustments can be made to the front passenger seat from the driver's seat.
Antilock device
The antilock device is implemented through a thermal fuse in the seat adjustment motors. As a result, if the respective seat adjustment motor is blocked, it is not switched off until it exceeds a certain temperature threshold.
| Electrical function schematic for seat adjustment (ESA) | PE91.29-P-2059-97XBB | ||
| Overview of system components for electric seats | GF91.29-P-9992FR |