GF80.20-P-0003CE Liftgate Control, Function
GF80.20-P-0003CE Liftgate Control, Function
MODEL 204.2
- with CODE (890) EASY-PACK liftgate as of model year 2009 /YoM 08
MODEL 204.9
- with CODE (890) EASY-PACK tailgate
A1 Instrument cluster
A2/71 Rear window antenna amplifier 1
A8/1 Transmitter key
B86/1 Left liftgate control obstruction sensor strip (on model 204.9)
B86/2 Right liftgate control obstruction sensor strip (on model 204.9)
H4/60 Tailgate control warning buzzer
M14/7 Tailgate central locking motor
M14/7s1 Tailgate rotary tumbler switch
M14/31 Tailgate locking element
M51/3 Tailgate control drive unit
M51/3b1 Tailgate control Hall sensor
M51/3b2 Tailgate control position sensor
M51/3m1 Tailgate control electric motor
N10/2 Rear SAM control unit with fuse and relay module
N69/1 Left front door control unit
N73 Electronic ignition switch control unit
N121/1 Tailgate control control unit
S15/3 Driver trunk lid/liftgate control button
S62/36 Tailgate control button
S88/8 Tailgate external operation switch
CAN B Interior CAN
CAN E Chassis CAN
Function requirements, general
^ Circuit 30g ON
^ No overvoltage or undervoltage
^ Liftgate control normalized
^ Speed v < 1 km/h (relevant as of circuit 15R ON)
^ Vehicle inclination < ± 20 %
The electronic ignition lock control unit sends the status of circuit 15 to the liftgate control unit via the interior CAN.
The instrument cluster sends the vehicle speed to the liftgate control unit via interior CAN.
The liftgate control must be normalized after replacing the liftgate control drive unit or after adjustment work.
Liftgate control, general
The liftgate can be opened or closed automatically from inside and outside via the liftgate control.
The liftgate control function comprises the following partial functions:
^ Function sequence for opening and closing request
^ Function sequence for opening liftgate
^ Function sequence for closing liftgate
^ Function sequence for opening angle limitation
^ Function sequence for obstacle detection
Function sequence for opening and closing request
The liftgate can opened and closed from the following control points:
^ Open/close liftgate button (model 204.9) on transmitter key
^ Driver trunk lid/liftgate control button
^ Liftgate control button (closing from outside)
^ Liftgate external operation switch (opening from outside)
The liftgate control unit reads in the control request via the interior CAN.
When the liftgate is opened or closed upon a request via the driver trunk lid/liftgate control button or liftgate open/close button the transmitter key, the liftgate control unit actuates the liftgate control warning buzzer twice when the liftgate is moving.
If requested via the liftgate external operation switch or liftgate control button, a warning tone does not sound.
If the liftgate control unit reads in another request while the liftgate is opening or closing, the liftgate drive stops.
Only when requested again, the drive is continued.
Except: Operation with transmitter key
When the liftgate close/open button on the transmitter key is actuated again after stopping, the liftgate moves in the opposite direction.
If the liftgate is positioned at the limitation point when the liftgate open/close button on the transmitter key is actuated, the liftgate is also moved in the opposite direction.
Open/close liftgate button (model 204.9) on transmitter key
When the liftgate open/close button on the transmitter key is pressed for t > 0.5 s, it transmits a radio signal to the electronic ignition lock control unit via the rear window antenna amplifier 1, rear SAM control unit and interior CAN. The electronic ignition switch control unit checks the access authorization of the transmitter key. If it is defined as valid, the electronic ignition lock control unit transmits the request "Open liftgate" or "Close liftgate" to the liftgate control unit via the interior CAN.
The transmitter key must be located in the direct vicinity of the vehicle.
The operation radius of the transmitter key (range of radio signal) corresponds to the central locking function.
Driver trunk lid/liftgate control button
The left front door control unit directly reads in the status of the driver trunk lid/liftgate control button and transmits this to the liftgate control unit via the interior CAN.
Tailgate control button
The rear control units directly reads in the status of the liftgate control button and transmits it to the liftgate control unit via the interior CAN.
On vehicles with code (889) KEYLESS-GO, the central locking can also be locked with the liftgate control button. Detailed information is given in the function description "KEYLESS-GO".
Tailgate external operation switch
The rear control units directly reads in the status of the liftgate external operation switch and transmits it to the liftgate control unit via the interior CAN.
Additional function requirements for opening liftgate
^ Liftgate rotary tumbler switch unlocked
Function sequence for opening liftgate
The liftgate control unit reads in the request "Open liftgate" via the interior CAN.
Then the liftgate control unit actuates the electric liftgate control motor in the opening direction until the liftgate control position sensor recognizes the upper limitation point or the opening angle limitation.
The position of the liftgate is defined by the rotation angle of the liftgate control position sensor.
When the liftgate control unit does not receive signals from the liftgate control position sensor, the actuation is of the electric liftgate control motor is stopped. Manual motion of the liftgate is possible with slightly increased force.
If the liftgate control drive unit is defective, it must be replaced completely.
Function sequence for closing liftgate
The liftgate control unit reads in the request "Close liftgate" via the interior CAN.
Then the liftgate control unit actuates the electric liftgate control motor in the closing direction until the rear SAM control unit recognizes when the liftgate arrests in the liftgate rotary tumbler over the liftgate rotary tumbler status.
Then the rear SAM control unit actuates the liftgate lock element (power closing).
The liftgate is now completely closed.
Function sequence for opening angle limitation
If required, the opening angle of the liftgate can be changed to prevent damaging the liftgate when extending objects are transported (skibox, surfboard, etc.).
First open liftgate to desired position to active opening angle limitation function. This can be accomplished manually or automatically via the liftgate control.
Manually:
After the liftgate is opened manually to the desired position, press liftgate control button for approx. t = 2 s.
Automatically:
If the liftgate is opened via the liftgate control, it is necessary to momentarily press the liftgate control button as soon as the liftgate is in the desired position. The liftgate remains in this position.
An upright drive is required for activation of the opening angle limitation function. Then press liftgate control button for approx. t = 2 s.
In both cases the adjustment of the opening angle of the liftgate is confirmed acoustically via the liftgate control warning buzzer.
When the liftgate is opened, it is only opened to this stored position.
The opening angle can be limited up to max. s = 20 cm in front of the mechanical stop of the liftgate.
The liftgate can be opened manually beyond the stored position.
To deactivate the opening angle limitation, actuate liftgate control button for t = 2 s (any liftgate position). The end of the opening angle limitation function is confirmed acoustically via the liftgate control warning buzzer (double tone):
Function sequence for obstacle detection
To recognize pinching of lock-up during the opening and locking procedure of the liftgate, the liftgate control unit evaluates the following parameters:
- Power consumption of electric liftgate control motor (obstacle recognized by power increase)
- Motion speed of liftgate via liftgate control position sensor (obstacle recognized by speed changes)
- Resistance of anti-pinch protection contact strips (on model 204.9) (pinching recognized by contact between interior conductors)
The anti-pinch protection contact strips are located on the left and right at the liftgate stop strip. The system recognizes when the pinch protection contact strip has been touched (contact with the internal conductor) by a change in the resistance.
If the liftgate control unit recognizes pinching or lock-up while closing, the electric liftgate control motor is reversed and the liftgate is moved back to the initial position.
During opening the electric liftgate control motor is switched off and the liftgate remains in the momentary position.
