LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 2015 >> ML350 Base >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Central Locking System - 166 Chassis >> Basic Knowledge >> Keyless Go, function >> Keyless Go, function - GF80.61-P-0005GN

Keyless Go, function - GF80.61-P-0005GN

MODEL 166 as of model year 2016 with CODE 889 (KEYLESS-GO) 

MODEL 166 as of model year 2016 with CODE 893 (KEYLESS-GO) 

MODEL 292 with CODE 889 (KEYLESS-GO) 

MODEL 292 with CODE 893 (KEYLESS-GO) 

Block diagram 

Fig 1: Keyless-Go Block Diagram
G10076933Courtesy of MERCEDES-BENZ USA

KEYLESS-GO, general 

The KEYLESS-GO comfort function allows keyless locking/unlocking of the vehicle as well as starting and switching off the engine without inserting the transmitter key into the electronic ignition lock control unit. It is sufficient to just carry the transmitter key.

IMPORTANT Operation of the central locking (CL) via the transmitter key remains possible parallel to the KEYLESS-GO functions.

The KEYLESS-GO comfort function consists of the following subfunctions:

IMPORTANT The anti-theft alarm system (ATA [EDW]) (with CODE 551 (Anti-theft alarm system (ATA [EDW]))) behaves in the same manner as when unlocking/locking the CL with the transmitter key.

Function sequence for position finding of transmitter key and access authorization code query 

To reliably or securely realize the locking/unlocking and engine start/stop function, it is necessary to determine the position of and authorize the transmitter key.

The following illustration indicates the components with the KEYLESS-GO control unit uses to detect the area around the vehicle or in the vehicle where the transmitter key is located.

KEYLESS-GO antenna overview, shown on model 166.0 

Fig 2: Overview Of Keyless-Go Antenna - Shown On Model 166.0
G10076934Courtesy of MERCEDES-BENZ USA

The position is determined when a capacitive sensor in a KEYLESS-GO door handle or the liftgate external operation switch is actuated. The KEYLESS-GO control unit directly reads in the signals from the capacitive sensors.

The rear SAM control units directly reads in the status of the liftgate external operation switch and transmits it to the KEYLESS-GO control unit via the interior CAN.

Then the KEYLESS-GO control unit transmits coded requests to the transmitter key via the KEYLESS-GO antennas. The transmitter key decodes these requests and transmits coded requests correspondingly when it is located in area A, B, C or D.

The KEYLESS-GO control unit receives the responses from the transmitter key via the rear window antenna and FM 1, AM, ZV and KEYLESS-GO antenna amplifiers and evaluates them. If the evaluation is positive, the KEYLESS-GO control unit authorizes the transmitter key.

IMPORTANT If the vehicle is loaded with unusual material (high volumes of metal) the long wave frequencies emitted by the KEYLESS-GO antennas for the KEYLESS-GO control unit are reflected or absorbed to a high degree, which can lead to erroneous detection. The maximum overlap between the detected interior and exterior area (measured at the side windows, windshield, or rear window) is approximately s = 10 cm. This means, the transmitter key is definitely located inside or outside the vehicle above s = 10 cm. Below 10 cm (gray zone), the position recognition for the key may be faulty. In everyday situations, this ensures that the driver can fill the fuel tank and that the child sitting inside the vehicle cannot start the engine as long as the driver has the transmitter key with him/her.

Additional function requirements for locking/unlocking 

IMPORTANT The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the KEYLESS-GO control unit.

Function sequence for locking/unlocking 

The locking/unlocking function allows the vehicle to be opened and closed via the CL.

The following control elements are available:

To lock and unlock:

To unlock:

To lock:

IMPORTANT The sensor units in the KEYLESS-GO door handles are switched off when circuit 15 is switched on. Activation takes place when circuit 15 is switched off and then a door is opened.

The locking/unlocking function comprises the following partial functions:

Function sequence for preadjustment of unlocking mode 

Basically the following types of unlocking are differentiated:

Simultaneously pressing the lock/unlock buttons on the transmitter key for t = 5 s, switches the system between two types of unlocking. The LED on the transmitter key comes on to confirm this change.

Function sequence for locking/unlocking one vehicle door 

Unlocking possibilities:

Locking possibilities:

Unlocking (example of global unlocking at the left front door):

When the left front KEYLESS-GO is held, the capacitive sensor in the door handle recognizes this.

The KEYLESS-GO control unit reads in the signal from the capacitive sensor and starts a query for the access authorization code.

IMPORTANT Detailed information on the signal path is available in the "Position finding of transmitter key and access authorization code query" chapter. When the access authorization code is valid, the electronic ignition lock control unit transmits the request "Unlock" via the interior CAN to the following control units:

The SAM control unit enables the opening request from the tank cap central locking actuator.

The opening request from the liftgate external operation switch is enabled to unlock the liftgate via the rear control unit.

The left rear door control unit unlocks the left front door lock via the left front doors central locking motor.

The right front door control unit unlocks the right front door lock via the left front door central locking motor.

The left rear door control unit unlocks the left rear door lock via the left rear door central locking motor.

The right rear door control unit unlocks the right rear door lock via the right rear door central locking motor.

The liftgate control unit (with CODE 890 (EASY-PACK liftgate)) starts automatic opening of the liftgate.

On vehicles with code (885) Extended theft protection, the following components are actuated additionally:

Function sequence for acoustic locking feedback 

The acoustic locking feedback function is selected via the control level in the instrument cluster.

The instrument cluster transmits the corresponding status via interior CAN to the SAM control unit.

When function is activated, the SAM control unit momentarily actuates the horns via the horn relay after successful locking or unlocking. For this purpose the electronic ignition lock control unit transmits the request "Lock" or "Unlock" to the SAM control unit via the interior CAN.

Number of acoustic signals:

IMPORTANT If a door or the liftgate is still open when locking, there is no acoustic feedback.

An opened front door is defined via the status of the front door safety catch microswitch. An opened rear door is defined via the status of the rear door safety catch microswitch. A opened liftgate is defined via the status of the liftgate rotary tumbler switch.

The front door control units and the rear door control units transmit the status of the respective safety catch microswitch via the interior CAN to the electronic ignition lock control unit. The rear control unit transmits the status of the liftgate rotary tumbler switch to electronic ignition lock control unit via the interior CAN.

Function sequence for optical locking feedback 

After the CL is locked or unlocked successfully, a visual feedback is output via the turn signals.

The electronic ignition lock transmits the request "Lock" or "Unlock" to the SAM control unit via the interior CAN. The SAM control unit then activates the hazard warning flasher function. All turn signals are actuated synchronously on the vehicle.

One flashing cycle is output when unlocking.

Three flashing cycles are output when locking.

IMPORTANT If a door or the liftgate is still open when locking, there is no acoustic feedback.

An opened front door is defined via the status of the front door safety catch microswitch. An opened rear door is defined via the status of the rear door safety catch microswitch. A opened liftgate is defined via the status of the liftgate rotary tumbler switch.

The front door control unit and the rear door control unit transmit the status of the corresponding rotary tumbler switch to the electronic ignition lock control unit via the interior CAN. The rear control unit transmits the status of the liftgate rotary tumbler switch to electronic ignition lock control unit via the interior CAN.

Additional function requirements for opening liftgate 

Function sequence for opening liftgate 

The liftgate is unlocked by pressing the external operation switch.

The rear SAM control units directly reads in the status of the external operation switch and transmits it to the KEYLESS-GO control unit via the interior CAN. The KEYLESS-GO control unit starts the query for the access authorization code.

IMPORTANT Detailed information on the signal path is available in the "Position finding of transmitter key and access authorization code query" chapter. When the access authorization code is valid, the electronic ignition lock control unit transmits the request "Unlock" via the interior CAN to the rear control unit.

The rear control unit unlocks the rotary tumbler of the liftgate via the liftgate central locking motor. On vehicles with CODE (890) EASY-PACK liftgate, the liftgate can be opened automatically.

Function sequence for closing liftgate and locking vehicle (with CODE 890 (EASY-PACK liftgate)) 

By actuating the liftgate control button, the liftgate is closed and the vehicle locked.

The rear SAM control unit directly reads in the status of the liftgate control button and transmits it to the KEYLESS-GO control unit via the interior CAN, which starts closing the liftgate.

After closing the liftgate the vehicle is locked with the CL unless a valid transmitter key is in the sensing range.

IMPORTANT Detailed information on the signal path is available in the "Position finding of transmitter key and access authorization code query" chapter.

IMPORTANT On vehicles with CODE 551 (Anti-theft alarm system (ATA [EDW])), the anti-theft alarm system (ATA [EDW]) is activated or deactivated with each type of locking or unlocking.

Additional function requirements for engine start/stop 

Function sequence for engine start/stop 

The function engine start/stop enables to engine to be started and switched off via the KEYLESS-GO start/stop button.

The engine start/stop function encompasses the following subfunctions:

Function sequence for interrogation of transmitter key 

The KEYLESS-GO control unit starts the check for an authorized transmitter key under the following conditions:

IMPORTANT The liftgate is evaluated as door.

The transmitter key is checked every s = 5 km. If a valid transmitter key has been found for 4 consecutive queries (s = 20 km), the KEYLESS-GO control unit does not start a new query until a door has been opened and closed again or if the vehicle was stationary (v = 0 km/h) and then sets off again.

If the vehicle stops and no door is opened, no new interrogation takes place as well.

IMPORTANT If a valid transmitter key is not recognized in the passenger compartment during a check, the instrument cluster outputs the message "Please insert key" in white letters in the multifunction display after the KEYLESS-GO start/stop button has been actuated five times. If no transmitter key is detected in the vehicle interior with the engine running (e.g. an accompanying person takes the transmitter key with him/her), the instrument cluster displays the message "Key not recognized" in red letters on the multifunction display. In this case it is possible to switch off the engine, however, it cannot be started. The transmitter key check is repeated every s = 1 km, and after s = 5 km the instrument cluster outputs the message "Key not recognized" in red letters in the multifunction display again. After 4 operations (s = 20 km), the message "Key not recognized" is indicated permanently and an acoustic warning is output.

Additional function requirements for starting engine 

IMPORTANT The fully integrated transmission control unit transmits the transmission selector lever position to the electronic ignition lock control unit via drive CAN, CDI control unit and chassis CAN 1.

The status of brake light switch is sent by the electronic ignition lock control unit over the chassis CAN 1 to the Electronic Stability Program control unit.

Function sequence for starting engine 

The engine is started when the KEYLESS-GO start/stop button is pressed.

The electronic ignition lock control unit directly reads in this request and transmits the status "Start/stop button pressed" via the interior CAN to the KEYLESS-GO control unit. The KEYLESS-GO control unit starts the query for the access authorization code.

IMPORTANT Detailed information on the signal path is available in the "Position finding of transmitter key and access authorization code query" chapter. If the access authorization code is valid, the electronic ignition lock control unit transmits the status of circuit 50 ON via chassis CAN 1 to the CDI control unit or the ME-SFI [ME] control unit and the engine is started.

Function sequence for display of fault messages 

The following situations lead to the output of fault messages: If no transmitter key is recognized in the vehicle interior after five activations of the KEYLESS-GO start/stop button, the message "Please insert key" is displayed on the instrument cluster. The start attempt is not started. The status of the circuit remains unchanged.

If, after startup (v > 0 km/h), a transmitter key is not detected in the passenger compartment, the instrument cluster outputs the message "Key not recognized" in red letters on the multifunction display.

If, during a start attempt, the transmission is not in position "P" or "N", an acoustic warning tone sounds and a corresponding message is output in the multifunction display of the instrument cluster.

The KEYLESS-GO control unit transmits the information to display error messages to the instrument cluster via the interior CAN.

The fully integrated transmission control unit transmits the transmission selector lever position to the instrument cluster via drive CAN, CDI control unit or ME-SFI control unit, chassis CAN 1, electronic ignition lock control unit and interior CAN.

Function sequence for circuit switching 

If the foot brake is not depressed when the KEYLESS-GO start/stop button is actuated, only circuit 15 R is switched on. Repeated actuation of the KEYLESS-GO start/stop button activates circuit 15. Actuating again, switches off circuit 15 R and circuit 15. If the driver door is closed, circuit 15 C remains active for t = 30 min.

Function sequence for shutting off engine 

When the KEYLESS-GO start/stop button is pressed when the engine is running, the engine is requested to shut down.

The electronic ignition lock control unit detects when the KEYLESS-GO start/stop button is pressed and transmits the status "Start/stop button pressed" to the KEYLESS-GO control unit via the interior CAN. The KEYLESS-GO control unit evaluates this and transmits the request "Shut off engine" via the interior CAN, electronic ignition lock control unit and chassis CAN 1 to the CDI control unit and ME-SFI control unit. The CDI control unit or ME-SFI control unit then shuts off the engine depending on the vehicle speed.

Switching off the engine depends on the vehicle speed:

The instrument cluster sends the vehicle speed to the KEYLESS-GO control unit via the interior CAN.

Electrical function diagram for Keyless Go PE80.61-P-2050-97NBA
Overview of system components for theft protection and locking GF80.00-P-9999GN 
scientia non olet · About LEMON Manuals