LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 2012 >> S550 Base >> Repair and Diagnosis >> Accessories & Equipment >> Interior/Illumination Lights >> Electrical System - Body - 221 Chassis - 01 Of 10 >> Basic Knowledge >> Panic Alarm System (PAS) Operation - GF82.25-P-0005SXS

Panic Alarm System (PAS) Operation - GF82.25-P-0005SXS

MODEL 221.1 with CODE (Z07) Top protection up to Model Year 08 Gefahrdeten-Alarm-System (GAS) 

Fig 1: Panic Alarm System (PAS) Communication Diagram
G10128815Courtesy of MERCEDES-BENZ USA

Function 

The panic alarm system (GAS) enables the vehicle occupants to secure the vehicle against intrusion from outside in the event of danger and to draw attention to an emergency situation using visual and acoustic alarm. Furthermore, it is also possible to use an intercom system to contact people outside. A two-way radio emergency call can also be made.

The open-loop control is responsible for the following control units:

Trigger panic alarm system (GAS) 

The panic alarm system (GAS) alarm can be triggered irrespective of the vehicle operating status (e.g. circuit 15 OFF, vehicle locked etc.).

The panic alarm system (GAS) alarm can be actuated using the following buttons:

When one of the three activate buttons is pressed a ground signal is sent to the corresponding signal of the PAS [GAS] and special signal system control unit and the Special vehicle multifunction control unit (SVMCU [MSS]). The PAS [GAS] and special signal system control unit discretely activates the alarm outputs. The special vehicle multifunction control unit (SVMCU [MSS]) actuates coded outputs discretely or over the interior CAN.

The following functions are actuated as standard.

Acoustic alarm 

The "YELP" electronic signal is emitted over an outside speaker mounted in an area of the vehicle. The frequency is generated by a sound generator integrated into the PAS [GAS] and special signal system control unit and sent discretely to the outside speaker.

Visual alarm 

Depending on the available lighting equipment in the vehicle different light actuators are activated by a panic alarm system (GAS). The difference is automatically made by the special vehicle multifunction control unit (SVMCU [MSS]) to match the variant coding. The special vehicle multifunction control unit (SVMCU [MSS]) then actuates the following lighting functions:

Turn signal lamps 

The special vehicle multifunction control unit (SVMCU [MSS]) transmits a "Turn signal lamps flashing quickly" message. The rear SAM control unit receives the request, generates a flashing frequency and then discretely actuates the rear turn signal lights.

The rear SAM control unit continues to send the flashing frequency over the interior CAN:

Close central locking (CL) 

In the event of a panic alarm system (GAS) alarm, the special vehicle multifunction control unit (SVMCU [MSS]) transmits "Close CL" over the interior CAN to the EIS [EZS] control unit. The EIS [EZS] control unit in response sends an "alarm close CL" over the interior CAN to the door control units. These then lock the doors via the door lock units.

The rear SAM control unit locks the filler cap over the fuel filler flap CL [ZV] motor and electrically blocks the trunk lid opening request of the trunk lid external operation switch (S88/8).

If one of the rear doors is in the first locking notch, the door is fully closed over the left rear door power closing (M14/23) or right rear door power closing (M14/24) and then locked. The trunk lid is completely closed and locked by the trunk lid CL [ZV] motor (M14/7).

IMPORTANT The driver- and front passenger door is not equipped with power closing.

If a door is still open the remaining doors are still closed. After the door that is still open is closed it is then also locked, even if the transmitter key (A8/1) is still in the EIS [EZS] control unit. This in turn means that there is a risk of being "locked out" of the vehicle.

The vehicle cannot be unlocked using the left interior CL [ZV] switch (S85/5) or right interior CL [ZV] switch (S85/6), as long as the special vehicle multifunction control unit (SVMCU [MSS]) transmits the "Close CL" request to the interior CAN.

The individual vehicle doors can also be opened from inside even during a panic alarm system (GAS) alarm.

Close air recirculation flap 

In the event of a panic alarm system (GAS) alarm, the special vehicle multifunction control unit (SVMCU [MSS]) transmits "Close air recirculation flap" over the interior CAN to the AAC[KLA] control unit. The AAC [KLA] control unit adjusts the fresh air/air recirculation flaps actuator motor to air recirculation mode, to prevent any air supply from outside and to prevent any penetration of unpleasant odors or harmful gases.

Make two-way radio emergency call (optional) 

On the special vehicle multifunction control unit (SVMCU [MSS]) the discrete output "two-way radio emergency call" is switched to ground.

A two-way radio can be used to make a two-way radio emergency call to an emergency center.

Depending on the programming involved the actuation of a two-way radio emergency call can take place in different ways.

The "Static" actuation mode is used when making a two-way radio emergency call to switch the discrete output on the special vehicle multifunction control unit (SVMCU [MSS]) to ground until the two-way radio emergency call actuation can be reset by pressing the microphone talk button on the inside microphone.

When making a two-way radio emergency call the "Pulse" actuation mode can be used to switch the discrete output on the special vehicle multifunction control unit (SVMCU [MSS]) twice to ground for 4 s each with an interval of 1 s.

Switch off panic alarm system (GAS) alarm 

Pressing the microphone talk button on the inside microphone switches a ground signal to the corresponding input of the PAS [GAS] and special signal system control unit and the special vehicle multifunction control unit (SVMCU [MSS]). The active alarm functions are deactivated.

The operating conditions of the previously switched-on standard components, such as the exterior lights, are active again and can be operated as usual.

The central locking can be unlocked again over the interior CL [ZV] switch and over the remote control of the transmitter key.

Panic alarm system (GAS) in combination with special signal system 

As long as the panic alarm system (GAS) is coupled with a special signal system, the panic alarm system (GAS) always has functional priority, i.e. if the alarms are switched on at the same time the special signal sequences and the special signal for the exterior lights are suppressed and super imposed by the previously described alarm functions. Only after pressing the microphone talk button on the inside microphone is the panic alarm system (GAS) alarm cleared and the special signal system re-activated.

Intercom system 

Fig 2: Panic Alarm System (PAS) With Special Signal System Flow Diagram
G10128816Courtesy of MERCEDES-BENZ USA

Intercom system 

Function requirement 

Function 

The intercom system can only be operated over the PAS [GAS] and special signal system control unit. The intercom system function does not have to be enabled, neither is any additional interlinking with other control units required.

The intercom system can be operated at any given time (irrespective of whether a panic alarm system (GAS) alarm is active or not).

Voice communications from outside to inside 

The intercom system is activated over a microphone switch on the inside microphone. In this operating condition external noise is audible or it is possible to speak to the vehicle occupants. The acoustic signals outside the vehicle are picked up by the outside mirror microphones and routed discretely to the PAS [GAS] and special signal system control unit.

The communication distance to the vehicle is between 3 m and 5 m depending on ambient noise. The PAS [GAS] and special signal system control unit amplifies the acoustic signals and the interior speaker is actuated over a discrete output. A speaker integrated into the inside microphone is also actuated so that in the event of any poor sound quality the inside microphone can be placed up against the ear to listen to.

IMPORTANT If a panic alarm system (GAS) alarm is triggered the "YELP" alarm signal is interrupted. The microphone switch on the inside microphone must always be switched off after use, as otherwise the "YELP" acoustic signal in the panic alarm system (GAS) alarm is not actuated.

Voice communications from inside to outside 

Pressing the microphone talk button on the inside microphone switches off the outside mirror microphones and the talk option is switched from inside to outside. The acoustic signals are pre-amplified in the inside microphone with 20 dB and sent discretely to the PAS [GAS] and special signal system control unit.

The PAS [GAS] and special signal system control unit amplifies this signal and feeds it via a discrete output to the outside speaker. The volume can be set using the control on the inside microphone.

IMPORTANT Pressing the microphone talk button on the inside microphone terminates an actuated panic alarm system (GAS) alarm.

  Panic alarm system (GAS), location of components   GF82.25-P-0005-01SXS 
  Panic alarm system (GAS), block diagram   GF82.25-P-0005-02SXS 
  Instrument cluster, component description A1 GF54.30-P-6000SX
  Driver-side SAM control unit with fuse and relay module, component description N10/1 GF54.21-P-6010SX
  Rear SAM control unit with fuse and relay module, component description N10/2 GF54.21-P-6030SX
  Xenon headlamp control unit, component description E1n1, E2n1
On vehicles with code (615) Bi-xenon headlamp unit with integrated curve illumination
GF82.10-P-2114SXA 
  Automatic air conditioning actuator motors, component description M2/5 GF83.40-P-2197SX
  Automatic air conditioning control unit, component description N22/1 GF83.40-P-3012SX
  PAS [GAS] and special signal system control unit, component description N26/12 GF82.25-P-3102SXS 
  Special vehicle multifunction control unit (SVMCU [MSS]), component description N26/14 GF54.21-P-4010SXS
  Driver-side front door control unit, component description N69/1 GF72.29-P-6000SX
  Passenger-side front door control unit, component description N69/2 GF72.29-P-6010SX
  Rear door control unit, component description N69/3, N69/4 GF72.29-P-6020SX
  Electronic ignition/starter switch control unit (EIS), component description N73 GF80.57-P-6000SX
  Central gateway control unit, component description N93 GF54.21-P-4170SX