Trunk Lid Control, Function - GF80.20-P-0012LFA

Model 217.3 

Model 222 

with code 881 (Remote boot-lid closing) 

Courtesy of MERCEDES-BENZ USA

Shown on model 217.3, 222 

Function requirements, general 

• Circuit 30g ON
• No overvoltage or undervoltage
• Trunk lid control normalized
• Speed below 1 km/h (relevant as of circuit 15R ON)
• Play protection on trunk lid lock not activated
• Transport mode not active

The trunk lid control must be normalized after replacing the trunk lid/liftgate control drive unit or after carrying out adjustment work on the trunk lid.

The electronic ignition lock control unit sends the status of circuit 15 via interior CAN to the trunk lid control unit. The instrument cluster sends the vehicle speed via user interface CAN, the electronic ignition lock control unit and interior CAN to the trunk lid control unit.

Trunk lid control, general 

The trunk lid can be opened and closed automatically from the inside or outside via the trunk lid control.

The trunk lid control function includes the following subfunctions:

• Request for opening or closing trunk lid 
• Open trunk lid 
• Close trunk lid 
• Normalizing trunk lid control 
• Opening angle limitation 
• Object recognition 

Request for opening or closing trunk lid 

The trunk lid can be opened or closed from the following control points:

• Trunk lid button on transmitter key (opening and for code P17 (KEYLESS-GO Package) also closing from outside) 
• Driver's trunk lid control button (opening and closing from inside) 
• Trunk lid control button (closing from outside) 
• Trunk lid external operation switch (opening from outside) 
• Rear switching module (opening and closing from outside) (with code 871 (HANDS-FREE ACCESS)) 
• Trunk lid emergency opening switch (only unlocking from inside) (with code 494 (USA version)) 
• Manual operation ("Tip to run") 

The trunk lid control unit reads in the each of the operating requirements via interior CAN.

If the trunk lid is opened or closed in vehicles with code 871 (HANDS-FREE ACCESS) due to a request via the rear switch module, the trunk lid control unit actuates the trunk lid control warning buzzer x 2 during the movement of the trunk lid.

If the trunk lid control unit reads in another request during opening or closing of the trunk lid, it stops the trunk lid drive. Only when requested again, the drive is continued. Except: Operation with transmitter key. A new request by pressing the open trunk lid button on the transmitter key after stopping always opens the trunk lid.

On vehicles with code 871 (HANDS-FREE ACCESS) when actuating again, the trunk lid is actuated in the opposite direction after stopping.

Trunk lid button on transmitter key (opening from outside and for code P17 (KEYLESS-GO Package) also closing from outside) 

When pressing the trunk lid open button on the transmitter key once for t = 0.5 s (without code 498 (Japanese version) or momentarily twice (with code 498 (Japanese version)), it transmits a radio signal via the rear window antenna and FM, AM, ZV, DAB and KEYLESS-GO control unit to the KEYLESS-GO unit. The KEYLESS-GO control unit sends this signal to the electronic ignition lock control unit via interior CAN.

The electronic ignition switch control unit checks the access authorization of the transmitter key. If it is valid, the electronic ignition lock control unit transmits the request "Open trunk lid" (if trunk lid is closed) and on vehicles with code P17 (KEYLESS-GO Paket) the request "Close trunk lid" (if trunk lid is opened) to the trunk lid control unit via the interior CAN.

The transmitter key must be located in the immediate vicinity of the vehicle when the trunk lid opens. The operating range of the transmitter key corresponds to the central locking function. When the trunk lid is closed, the transmitter key must be located in the immediate vicinity of the vehicle (transmitter key position finding). If the trunk lid button is pressed again while opening or closing the trunk lid, the drive is stopped.

Driver's trunk lid control button (opening and closing from inside) 

When actuating the driver trunk lid control button, the trunk lid can be opened, to close hold down driver trunk lid control button.

The left front door control unit directly reads in the status of the driver trunk lid control button and transmits it to the trunk lid control unit and rear SAM control unit via the interior CAN.

Trunk lid control button (closing from outside) 

The rear SAM control unit directly reads in the status of the trunk lid control button and transmits this via the interior CAN to the trunk lid control unit and the rear SAM control unit.

Model 217.3

with code 889 (KEYLESS-GO)

Model 222

with code 881 (Remote boot-lid closing)

with code 889 (KEYLESS-GO)

The central locking system can also be locked via the trunk lid control button.

Trunk lid external operation switch (opening from outside) 

The rear SAM control unit reads in the status of the trunk lid external operation switch directly and sends this via interior CAN to the trunk lid control unit.

Additional function requirements for rear switching module (opening and closing from outside) (with code 871 (HANDS-FREE ACCESS)) 

• Circuit 15 OFF
• Transmitter key is located behind the vehicle in the KEYLESS-GO detection range

Rear switching module (opening and closing from outside) (with code 871 (HANDS-FREE ACCESS)) 

The trunk lid can be opened and closed without touching using the rear switching module. The function is actuated by foot motion ("kicking motion") in the rear of the rear switching module below the bumper.

The rear switching module directly reads in the signals from rear switching module sensors, evaluates them and transmits the corresponding request to the KEYLESS-GO control unit via the KEYLESS-GO LIN. The KEYLESS-GO control unit transmits this request via the interior CAN, electronic ignition lock control unit and interior CAN to the trunk lid control unit.

The trunk lid control unit actuates the trunk lid control buzzer twice when the trunk lid is moved.

Trunk lid emergency opening switch (only unlocking from inside) (with code 494 (USA version)) 

This function is always active (regardless of the status of the CL [ZV]) because it is intended to allow the trunk lid to be unlocked by a person trapped in the trunk.

The rear SAM control unit directly reads in the status of the trunk lid emergency opening switch and unlocks the trunk lid via the trunk lid central locking motor.

Additional functional requirements for manual operation ("Tip to run") 

• Trunk lock main catch switch not engaged in trunk lock

Manual operation ("Tip to run") 

The trunk lid can be opened and closed automatically via manual actuation. This function is triggered by pressing or pulling the trunk lid to the desired direction.

Actuation is recognized by the trunk lid control position sensor. The trunk lid control unit directly reads in the signals from the trunk lid control position sensor.

The pushing or pulling direction is relevant for triggering of the function, i. e. the control request must be detected e.g. in order to prevent the function from being triggered by a gust of wind.

Additional function requirements for opening trunk lid 

• Opening request is present

Open trunk lid 

The rear SAM control unit unlocks the trunk lid via the trunk lid/liftgate lock motor. The trunk lid control unit reads in the "Open trunk lid" request via interior CAN. Then the trunk lid control unit actuates the trunk lid/liftgate control electric motor in the opening direction until the trunk lid control unit recognizes the upper limit or the opening angle limit. The position of the trunk lid is determined via the rotation angle of the trunk lid/liftgate position sensor.

If the trunk lid control unit does not receive any signals from the trunk lid position sensor, the actuation of the trunk lid control electric motor is stopped. Manual movement of the trunk lid is possible with slightly increased use of force. The entire trunk lid control drive unit must be replaced if defective.

Additional function requirements for closing trunk lid 

• Closing request is present

Close trunk lid 

The trunk lid control unit reads in the "Close trunk lid" request via interior CAN. Then the trunk lid control unit actuates the trunk lid control electrical motor in the closing direction until the trunk lid lock safety catch switch (start power closing) is actuated. The rear SAM control unit reads in the status of the trunk lid lock safety catch switch directly and transmits the status via the interior CAN to the trunk lid control unit. Then the trunk lid control unit stops the drive.

The rear SAM control unit starts the power closing function and actuates the trunk lid lock element (as of 01.06.2017 (model 222) and/or 01.12.2017 (model 217)) and/or the trunk lock motor (up to 31.05.2017 (model 222) and/or 30.11.2017 (model 217)) until the trunk lock main catch switch is actuated. The trunk lid is now fully closed. The rear SAM control unit directly reads in the status of the trunk lid lock main catch switch.

Normalizing trunk lid control 

The trunk lid control must be normalized after replacing the trunk lid control drive unit or after adjustment work on the trunk lid.

Normalization is the basis for association of the current position of the trunk lid in relation to the position determined by the trunk lid control unit. Normalization means learning in the upper and lower end position of the trunk lid (zero position).

When synchronizing automatically, the trunk lid is opened in one cycle up to the upper end position. After the trunk lid is stopped for approx. 2 s, this position is learned as upper end position. Then the trunk lid is closed completely at a constant speed until the trunk lid lock safety catch switch is pressed (start power closing). The rear SAM control unit starts the power closing function. The value of the trunk lid position sensor that is read in after actuating the trunk lid/liftgate lock main catch switch is set as the lower end position.

The trunk lid control unit actuates the trunk lid control electric motor accordingly.

The rear SAM control unit reads in the status of the trunk lid lock safety catch switch and the status of the trunk lid main catch switch directly.

Opening angle limitation 

The opening angle limitation function is used to determine a new trunk lid end position of the trunk lid (garage position or maximum opening) to prevent damage to the trunk lid by protruding cargo (ski box, surfboard, etc.). The "garage position" is a specified intermediate position (approx. 50 % opening width) that can be activated/deactivated or defined as a new end position via a menu in the head unit (as of 01.06.2017 (model 222) and/or 01.12.2017 (model 217)) and/or in the COMAND control unit (up to 31.05.2017 (model 222) and/or 30.11.2017 (model 217)).

As of 01.06.2017 (model 222) and/or 01.12.2017 (model 217): 

The following options are available for navigation in the operating menu of the head unit:

• With code 448 (Touchpad), navigation can be performed with the Audio/COMAND control panel. The audio/COMAND control panel (except code 446 (Touchpad only)) transmits the corresponding signals via telematics CAN to the head unit.
• With code 446 (Touchpad only) or code 448 (Touchpad) navigation is possible with the touchpad. The touchpad (with code 446 (Touchpad only) or code 448 (Touchpad)) transmits the corresponding control signals via telematics CAN to the head unit.
• Navigation can be performed by voice control. The driver hands-free system microphone is read directly by the head unit.
• Navigation can be performed via the head unit finger navigation pad and the "Back" button on the steering wheel. The head unit finger navigation pad and the "Back" button transmit the corresponding operation signals via the steering wheel electronics, steering wheel CAN, steering column tube module control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.
• With code 448 (Touchpad), the operating menu can be called via the "CAR" button on the Audio/COMAND control panel. The Audio/COMAND control panel transmits the "CAR" button status via the telematics CAN to the head unit.

  With code 446 (Touchpad only), the operating menu can be called via the "CAR" button on the lower control panel. The lower control panel transmits the "CAR" button status via the LCP-LIN, touchpad and telematics CAN to the head unit.

The heat unit transmits the request via user interface CAN, electronic ignition lock control unit and interior CAN to the trunk lid control unit. The head unit generates the corresponding image data and sends a switch-on request to the Audio/COMAND display via telematics CAN. The image data is transmitted via HSVL line to the audio/COMAND display.

Up to 31.05.2017 (model 222) and/or 30.11.2017 (model 217): 

The Audio/COMAND operating unit is used to operate it. The COMAND control unit reads in the operation request from the Audio/COMAND control panel via the telematics CAN and transmits the request for opening angle limitation via the user interface CAN, the electronic ignition lock control unit and the interior CAN to the trunk lid control unit.

It is displayed in the audio/COMAND display. The COMAND control unit generates the corresponding image data and sends a switch-on request to the Audio/COMAND display via telematics CAN. The image data is transmitted via the HSVL line to the Audio/COMAND display.

Object recognition 

In order to recognize an obstacle during the opening and closing procedure of the trunk lid (e.g. pinching or locking up), the trunk lid control unit evaluates the signals from the trunk lid position sensor and the power consumption of the trunk control drive unit.

If an obstacle is detected by the trunk lid control unit via the trunk lid control position sensor during the closing of the trunk lid, the trunk lid control unit immediately cancels the closing process and opens the trunk lid until the start position before the closing process is reached. In the case of object recognition during the opening process, the trunk lid control unit cancels the opening process. The trunk lid remains in the momentary position.

	Electrical function schematic for trunk lid control		PE88.50-P-2051-97SEB
	Overview of system components for theft protection and locking		GF80.00-P-9999LF