GF80.20-P-0001TA Tailgate Remote Actuation, Function

GF80.20-P-0001TA Tailgate remote actuation, function
- with CODE (890) Automatic tailgate


Overall description of system
The tailgate remote control allows the tailgate to be opened with the remote control key (A8/1) (radio signal) and the tailgate remote opening switch (S15) in the driver's door. In comparison to the tailgate remote opening feature the tailgate remote closing feature represents an expansion of the operating convenience. The tailgate remote closing feature allows the tailgate to be opened and closed hydraulically.Vehicles with tailgate remote actuation are equipped with an additional hydraulic system, a sensor and additional operating switches

The hydraulic opening feature for the tailgate can be started with the following controls:
^ Via radio with the remote control key (A8/1)
^ From vehicle passenger compartment with tailgate remote opening switch (S15)
^ On tailgate with tailgate exterior control switch (S88/8)

The tailgate can be opened in this way up to the end stop The opening movement can be stopped at any point and continued again.

Limitation of opening position
The so-called garage position can be activated and deactivated with the second control level on the instrument cluster (A1) in the vehicle menu with the submenu tailgate/trunk lid opening limitation The tailgate then opens to a defined position when this function is active.

A hydraulic closing of the tailgate is possible via the following switch:
^ on the tailgate with the tailgate switch (S62/36)

For safety reasons it is not possible to close the tailgate using the remote control feature with the remote control key (A8/1) or remote tailgate opening switch (S15) During the hydraulic closing operation, the hydraulic system closes the tailgate just to the point that it can catch in the lock automatically with its own weight The tailgate hydraulic pump (M51/1) is switched off before the tailgate catches in the lock

The power locking feature then takes over final closing of the tailgate.

The entire control for the "opening" and "closing" processes is accomplished by the tailgate closing control module (N121/1). The tailgate closing control module (N121/1) reads in the signal from the trunk lid/tailgate opening angle recognition sensor (B24/16) and starts the tailgate hydraulic pump (M51/1)

The tailgate hydraulic pump (M51/1) builds up the pressure for the hydraulic cylinder The linear motion of the hydraulic cylinder is converted to a rotary motion by an articulated hinge allowing the tailgate to the opened and closed hydraulically. The weight of the tailgate is compensated by two additionally installed gas pressure struts

Safety mechanism
The trunk lid/tailgate opening angle recognition sensor (B24/16) allows the tailgate closing control module (N121/1) to check the end switch-off points and hydraulic operation of the tailgate. The tailgate hydraulic pump (M51/1) is switched off upon reaching the final switch-off angle in each case.

With the aid of the trunk lid/tailgate opening angle recognition sensor (B24/16) , the tailgate closing control module (N121/1) evaluates not only the current opening angle of the tailgate but registers as well speed changes in the tailgate motion.

When the tailgate hits against an obstacle or is manipulated manually, the speed of the tailgate changes

In such cases the tailgate closing control module (N121/1) stops the hydraulic opening motion and reverses the direction of motion of the tailgate during the closing operation

If necessary, manual actuation of the tailgate is possible, however, requires increased force, because it is also necessary to move the hydraulic mechanism. The trunk lid/tailgate opening angle recognition sensor (B24/16) must not be recalibrated following manual actuation.

For safety reasons, the tailgate closing control module (N121/1) switches off the tailgate hydraulic pump (M51/1) after a maximum continuous operating time of t = 20 s.

Special case for automatic extending main cargo floor, code 943
If the vehicle is equipped with an automatic extending main cargo floor code 943 the state of the cargo floor (extended/ retracted) has an effect on the operation of the automatic tailgate closing feature. If the cargo floor is not completely retracted (status signal from cargo floor control module (N130) via CAN interior compartment bus and a request to close the tailgate is present at the tailgate closing control module (N121/1) , the latter sends a warning signal to the tailgate control module (N111) via the CAN interior compartment bus which causes the cargo floor switch (S150) to flash This warning signal remains set as long as the request "Close tailgate" is present on the tailgate closing control module (N121/1) The cargo floor switch (S150) flashes for a maximum of 25 s under the control of the tailgate control module (N111) It is then necessary for the tailgate control module (N111) to send a new warning signal via the CAN interior compartment bus.