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Home >> Mercedes Benz >> 2012 >> E 350 4MATIC Wagon (212.288) V6-3.5L (276.952) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Police / Special Vehicle Options >> Description and Operation >> GF82.25-P-2011FL Emergency Alarm Function

GF82.25-P-2011FL Emergency Alarm Function



GF82.25-P-2011FL Emergency Alarm Function
- with CODE (965) Electrical preinstallation for rental vehicles
- with CODE (934) Taxi emergency alarm system


Function requirements, general
^ Circuit 30 ON

Emergency alarm, general

The emergency alarm function is a protective device for the taxi driver. The emergency alarm can be triggered by the taxi driver he/she feels threatened by someone. At the same time, a radio help call can also be triggered.
The emergency alarm function consists of the following partial functions:
^ Function sequence for emergency alarm
^ Function sequence for radio help call
^ Function sequence for display of fault messages

Function sequence for emergency alarm

The emergency alarm can be activated via the taxi emergency alarm system radio remote triggering transmitter (A8/4) (full alarm) or via the taxi emergency alarm system "Trigger" button (S62/6) concealed in the driver footwell.
An active emergency alarm is ended by pressing the taxi emergency alarm system "Delete" button (S62/5).

Depending on the programming, a radio help call can also be triggered.

The following variants of the emergency alarm can be output:
^ Function sequence for silent alarm
^ Function sequence for full alarm

Function sequence for silent alarm
The silent alarm should prevent the threatening person from noticing the alarm triggering.
The silent alarm is requested by pressing the "Trigger" button once. The special-purpose vehicle multifunction control unit (N26/9) reads in the status of the "Trigger" button directly, evaluates this and actuates the roof sign lamp (E14/4) (with code (342) Roof sign connection for taxi) with a frequency of f = 2.5 Hz.

Function sequence for full alarm
In the event of a full alarm, the following functions are also triggered in addition to the output of the silent alarm:
- Exterior lights (flashing)
- Interior illumination (static)
- Acoustic alarm

The full alarm is requested by actuating the "Trigger" button or the radio remote triggering transmitter twice within t = 3 s.

The multifunction control unit directly reads in the status of the "Trigger" button.

The request for full alarm via the radio remote triggering transmitter is received by the multifunction control unit via the following route:
- Radio remote triggering transmitter radio signal
- FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18)
- Direct line
- Rear SAM control unit with fuse and relay module (N10/2)
- Interior CAN (CAN B)
- Front SAM control unit with fuse and relay module (N10/1)
- Interior CAN
- Electronic ignition lock control unit (N73)
- Interior CAN

For safety reasons, the request for the full alarm via the remote triggering transmitter is automatically repeated after t = 30 s.

The multifunction control unit evaluates the request and sends corresponding information via interior CAN to the front SAM control unit, which then evaluates this and initiates the output of the alarm. To do so, it sends the information via interior CAN to the following control units:
- Rear SAM control unit
- Left front door control unit (N69/1)
- Right front door control unit (N69/2)
- Left rear door control unit (N69/3)
- Right rear door control unit (N69/4)
- Multifunction control unit
- Overhead control panel control unit (N70) (with code (414) Power glass tilting/sliding sunroof)

The electronic overhead control panel (N70/3) (without code (414) Power glass tilting/sliding sunroof) is actuated by the front SAM control unit.

Exterior lights:
During output of the full alarm, the following functions are actuated to flash:
- Hazard warning flasher actuation
- Standing lamp actuation
- Low beam and high beam actuation
- Front fog light actuation
(without code (615) Bi-xenon headlamp unit with integrated curve illumination, without code (616) Bi-xenon headlamp unit with integrated asymmetrical curve illumination, without code (621) Intelligent Light System (left-hand traffic) and without code (622) Intelligent Light System (right-hand traffic))

Detailed information on the actuation of individual components of the exterior lights can be found in the separate exterior lights function description.

Interior illumination:
Detailed information on the actuation of individual components of the interior illumination can be found in the separate interior illumination function description.

Acoustic alarm:
The front SAM control unit actuates the left horn (H2) and the right horn (H2/1) with a frequency of f = 1.6 Hz.

Function sequence for radio help call
Depending on the programming, a radio help call can be made separate from or together with the emergency alarm.
The radio help call is started by:
- Pressing the "Trigger" button once
- Pressing the "Trigger" button twice within t = 3 s
- Operating the radio remote triggering transmitter twice within t = 3 s

The request for the radio help call is recognized by the multifunction control unit and forwarded via multifunction CAN (CAN K) to the two-way radio (A49) (accessories) or the radio data transmission two-way radio (A49/5) (accessories).

The two-way radio or radio data transmission two-way radio forwards the signal to the multifunction antenna (A28/11) via the following route to be sent:
- Direct line
- Taxi telephone antenna splitter (A28/12)
(with code (386) Comfort telephony)
- Direct line
- Antenna amplifier/cellular telephone system compensator (A28/3)
(with code (386) Comfort telephony)
- Direct line
- Mobile phone and stationary heater radio remote control antenna splitter (A2/53) (with code (386) Comfort telephony)
- Direct line

The radio help call is then made via the multifunction antenna to the taxi main office.
Depending on the programming, the actuation of a radio help call can occur "statically" or as a "pulse".

With the "static" actuation, the discrete output at the multifunction control unit is switched to ground when the radio help call is made until the request for the radio help call is reset via the "Delete" button.
With the "pulse" actuation, the discrete output at the multifunction control unit is switched to ground twice for t = 1 s when the radio help call is made, with a break of t = 1 s between the pulses.

An active radio help call is ended by pressing the "Delete" button. Often, however, it is necessary to restart the two-way radio in order to reset the radio help call in the two-way radio.

Function sequence for display of fault messages
The fault messages are shown in the multifunction display (A1p13) of the instrument cluster (A1).
Faults and malfunctions that occur are recognized and stored by the multifunction control unit and sent via interior CAN to the instrument cluster.

In addition, the multifunction control unit cyclically sends data protocols via interior CAN to the instrument cluster.

The following faults and malfunctions are shown in the multifunction display:
- Interruption in the communication between the multifunction control unit and the instrument cluster
- Interruption of the line to the "Trigger" button
- Interruption of the line to the "Delete" button
- Alarm triggering recognized but neither emergency alarm nor radio help call activated

During diagnosis via the diagnostic tester, a corresponding message is also shown in the multifunction display.





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