Seat release in 2nd seat row, function

P91.29-2918-79

Function requirements, general

 Respective function activated in the variant coding

Seat release, 2nd seat row, general

In order to make access to the 3rd seat row easier, the seats in the 2nd row can be released and folded down manually or electrically (with CODE 843 (EASY-ENTRY electric)). The seats are always returned to their original position manually.

The 2nd seat row seat release includes the following subfunctions:

 Function sequence for EASY-ENTRY (except CODE 843 (EASY-ENTRY electric))

 Function sequence for Power EASY-ENTRY (with CODE 843 (EASY-ENTRY electric))

Function sequence for EASY-ENTRY (except CODE 843 (EASY-ENTRY electric))

The left or right rear seat of the 2nd seat row can be released manually and then folded down to the EASY-ENTRY position.

When folding down the rear seats, the respective 2nd seat row easy entry/exit switch is closed. The rear control unit reads in the status of the 2nd seat row easy entry/exit switch directly and sends the signal "Left/right rear seat released" via interior CAN to the instrument cluster, which shows a corresponding message in the multifunction display.

Collision avoidance with CODE 275 (Memory package (driver seat, steering column, mirror)) or CODE P64 (Memory package):

In order to avoid collisions with the front seats when folding down the rear seats, the driver or front passenger seat (with CODE P64 (Memory package)) is moved to the EASY-ENTRY position.

When folding down the rear seats, the respective 2nd seat row easy entry/exit switch is closed. The rear control unit reads in the status of the 2nd seat row easy entry/exit switch directly and sends the signal "Left/right rear seat released" via interior CAN to the driver seat control unit or to the front passenger seat control unit (with CODE P64 (Memory package)).

The driver seat control unit or the front passenger seat control unit (with CODE P64 (Memory package)) then actuates the following motors:

 Seat adjustment motor, seat fore/aft adjustment

 Seat adjustment motor, height adjustment

 Seat adjustment motor, backrest inclination

The respective front seat is moved to the EASY-ENTRY position. To detect the position, the signals from the corresponding Hall sensors are read in directly by the driver seat control unit or the front passenger seat control unit (with CODE P64 (Memory package)) and evaluated.

 The function is ended upon folding back and locking the rear seats. The respective front seat does not automatically move back to its original position, but has to be manually adjusted as required.

Additional function requirements for Power EASY-ENTRY (with CODE 843 (EASY-ENTRY electric))

 Vehicle speed v  2 km/h

 Respective rear door open

 The instrument cluster sends information on the vehicle speed via interior CAN to the rear control unit.
Each rear door control unit sends the status of the corresponding rear door (open/closed) over the interior CAN to the rear control unit.

Function sequence for Power EASY-ENTRY (with CODE 843 (EASY-ENTRY electric))

The left or right rear seat of the 2nd seat row can be brought into the EASY-ENTRY position by pressing the corresponding 2nd seat row folding backrest switch. Pressing again is not necessary.

The status of the 2nd seat row folding backrest switch is read in directly by the rear control unit. After the function has been triggered on the left side, the rear control unit actuates the head restraint motor on 2nd seat row at left and the head restraint motor on 2nd seat row at center directly. After the function has been triggered on the right side, the rear control unit actuates the head restraint motor on 2nd seat row at right directly. The head restraints are being lowered.

Following this, the respective rear seat is released and folded forward by mechanical spring force. To do so, the rear control unit actuates the corresponding 2nd seat row release unit directly.

When folding down the rear seats, the respective 2nd seat row easy entry/exit switch is closed. The rear control unit reads in the status of the 2nd seat row easy entry/exit switch directly and sends the signal "Left/right rear seat released" via interior CAN to the instrument cluster, which shows a corresponding message in the multifunction display.

Collision avoidance with CODE 275 (Memory package (driver seat, steering column, mirror)) or CODE P64 (Memory package):

In order to avoid collisions with the front seats when folding down the rear seats, the driver or front passenger seat (with CODE P64 (Memory package)) is moved to the EASY-ENTRY position.

The status of the 2nd seat row folding backrest switch is read in directly by the rear control unit. After the function has been triggered, the rear control unit sends the signal "Left/right rear seat released" via interior CAN to the driver seat control unit or to the front passenger seat control unit (with CODE P64 (Memory package)).

The driver seat control unit or the front passenger seat control unit (with CODE P64 (Memory package)) then actuates the following motors:

 Seat adjustment motor, seat fore/aft adjustment

 Seat adjustment motor, height adjustment

 Seat adjustment motor, backrest inclination

The respective front seat is moved to the EASY-ENTRY position. To detect the position, the signals from the corresponding Hall sensors are read in directly by the driver seat control unit or the front passenger seat control unit (with CODE P64 (Memory package)) and evaluated.

 The function is ended upon folding back and locking the rear seats. The respective front seat does not automatically move back to its original position, but has to be manually adjusted as required.

 Play protection:
Play protection is integrated in order to protect the 2nd seat row head restraint motors from overheating. After each actuation, a counter is increased by one. After a certain time, the value of the counter is decreased by one, independently of other actuations. If the counter reaches a value of zero, no further reduction occurs. Provided that the counter is smaller that the play protection limit setting, actuations are allowed. If the counter reaches the play protection limit, the next actuation is only possible after a certain time. Function activations are ignored during this time. The waiting times and the play protection limit can be parameterized using the diagnostic tester.