Anti-theft alarm system trigger, function

Function requirements, general

 Anti-theft alarm system (ATA) activated

Anti-theft alarm system alarm triggering, general

If one of the alarm inputs changes its non-actuated state when the ATA is activated, the ATA alarm is triggered.

 Alarm actuation in the event of undervoltage:

The operating voltage range of the ATA [EDW] is defined from U = 8.5 to 15.5 V. If the voltage is U  8.5 V, a direct visual alarm output is not possible. Only an acoustic alarm is triggered. The battery voltage is stored in the ATA alarm memory in the rear SAM control unit with fuse and relay module (N10/2).

The ATA [EDW] alarm triggering function comprises the following partial functions:

 Function sequence for alarm triggering by opening door, trunk lid, engine hood, center console compartment or glove compartment

 Function sequence for alarm triggering by changing the vehicle inclination (with CODE 882 (Interior monitoring))

 Function sequence for alarm triggering by movement in the vehicle interior (with CODE 882 (Interior monitoring))

 Function sequence for alarm triggering from communication loss to alarm siren (H3/1)

(without code 494 (USA version))

 Function sequence for triggering alarm by emergency opening (with code (494) USA version)

 Function sequence for alarm triggering by panic switch (with code 763 (Radio remote control with panic switch))

 Function sequence for alarm output

Function sequence for alarm triggering by opening door, trunk lid, engine hood, center console compartment or glove compartment

The rear SAM control unit actuates an alarm as soon as the non-actuated state of one of the following switches is interrupted for t > 0.5 s:

 Pedestrian protection Hall sensor + engine hood ATA switch (A38/1) (with code U60 (Active engine hood (pedestrian protection)) up to 31.05.2015)

 Left door lock rotary tumbler switch (A85s1) in left door lock(A85)

 Right door lock rotary tumbler switch (A85/1s1) in right door lock (A85/1)

 Trunk lid rotary tumbler switch (M14/7s1) in trunk lid central locking motor (M147)

 Glove compartment anti-theft alarm system switch (S62/7)

 Center console stowage compartment anti-theft alarm system switch (S62/32)

 Left engine hood contact switch (S62/43) (as of 01.06.2015)

 Left engine hood contact switch (without code U60 (Active engine hood (pedestrian protection)) up to 31.05.2015)

The status of the left door lock rotary tumbler switch is read in by the left door control unit (N69/1), the status of the right door lock rotary tumbler switch by the right door control unit (N69/2) and relayed to the rear SAM control unit via the interior CAN. The remaining switches are read in by the rear SAM control unit.

For a new alarm actuation, the corresponding switch must first change to the non-actuated state (debounce time t = 500 ms).

After a non-actuated state of t = 10 s an alarm can be reactuated by the same switch, if an acoustic alarm is not present.

 If a locked vehicle is unlocked with the emergency key and then a door is opened. the aTA triggers an alarm.

Additional function requirements for alarm triggering by changing the vehicle inclination (with CODE 882 (Interior monitoring))

 Tow-away protection not deactivated

Function sequence for alarm triggering by changing the vehicle inclination (with CODE 882 (Interior monitoring))

If the inclination sensor integrated into the interior protection sensor (A26/13) recognizes an alarm-relevant change of inclination, an alarm is output. The corresponding signal is read via the rear SAM-LIN (LIN B4) by the rear SAM control unit.

Actuation criterion:

 Change in vehicle inclination (horizontal axis) 1° to -1°, 0.2°

 Alarm is triggered before a wheel looses ground contact when lifting the vehicle.

Additional function requirements for alarm triggering by movement in the vehicle interior (with CODE 882 (Interior monitoring))

 Interior protection not deactivated

Function sequence for alarm triggering by movement in the vehicle interior (with CODE 882 (Interior monitoring))

The interior protection sensor transmits radar waves into the vehicle interior. These are received and evaluated by the interior protection sensor.

If a movement in the vehicle interior is recognized and considered to be alarm-relevant, an alarm is output. For this purpose the interior protection sensor transmits corresponding requests via the rear SAM-LIN to the rear SAM control unit which then starts the alarm output.

Function sequence for alarm triggering from communication loss to alarm siren (without CODE 494 (USA version))

The alarm siren is actuated cyclically approx. every t = 700 ms by the rear SAM control unit with rear SAM-LIN. If a reply to this request is not received within t = 1 s by the alarm siren (no communication), the rear SAM control unit and alarm siren trigger an alarm.

If the alarm siren detects an change of the supply voltage or data line, it also outputs automatically an acoustic alarm.

 An alarm is only repeated if a new alarm event is registered after the active acoustic alarm was terminated.

Function sequence for triggering alarm by emergency opening (with code (494) USA version)

The trunk lid emergency opening switch (S8810) ensures that the trunk lid can also be opened from the inside of the trunk lid when the vehicle is locked. The status of the trunk lid emergency opening switch is read in and evaluated by the rear SAM control unit.

The ATA [EDW] triggers an alarm when the trunk lid emergency opening switch is actuated.

Addi tonal function requirements for alarm actuation by panic switch (with code 763 (Radio remote control with panic switch))

 Circuit 15C OFF

Function sequence for alarm triggering by panic switch (with code 763 (Radio remote control with panic switch))

With the panic alarm it is possible to trigger the visual and acoustic antitheft alarm (ATA [EDW]) with the transmitter key (A8/1) (e.g. in an emergency).

 Function sequence when panic alarm and ATA alarm are triggered simultaneously:
The panic alarm has priority over the ATA alarm.
If both alarms are actuated the alarm with the higher priority is output and the ATA alarm is suppressed. This alarm is still actuated in the background. If one of the two alarms is terminated or is interrupted, the other is still actuated.

The alarm triggering with the panic switch comprises the following subfunctions:

 Function sequence for actuating panic alarm

 Interrupting function sequence for panic alarm

Function sequence for actuating panic alarm

When the panic alarm button the transmitter key is actuated for t  2 s, it transmits a radio signal with the authorization access code via the FM, AM and ZV antenna amplifier (A2/18) to the electronic ignition lock control unit (N73).

Parallel to the radio signal, the transmitter key (as of 01.06.2015 without code 889 (KEYLESS-GO)) transmits an infrared signal with access authorization code via driver door infrared remote control receiver (A26/1) (precise aiming required) and a direct line to the left door control unit (N69/1). The left door control unit transmits this to the electronic ignition lock control unit via the interior CAN (CAN B).

 The infrared and radio signals contain the same information (redundant). The first signal received always has priority. This function serves for operating safety in the event that the radio signal is blocked by interference such as electromagnetic fields.

The electronic ignition lock control unit checks the transmitter key's access authorization code in both cases.

If the access authorization is valid, the electronic ignition switch control unit transmits the request "Activate panic alarm" to the rear SAM control unit with fuse and relay module (N10/2) via the interior CAN. The rear SAM control unit actuates an ATA [EDW] alarm.

Interrupting function sequence for panic alarm

The panic alarm is interrupted when the panic alarm button on the transmitter key is actuated briefly.

The function sequence for interrupting the panic alarm is the same as for actuating the panic alarm.

Function sequence for alarm output

Visual alarm output:

When an ATA [EDW] alarm is triggered, the rear SAM control unit requests the hazard warning flashing function via interior CAN.

The front SAM control unit generates a corresponding flasher frequency that is output via interior CAN.

All turn signals are actuated synchronously on the vehicle.

The interior lights are switched on by the front SAM control unit.

 Detailed information on implementing the hazard warning flasher function or interior illumination is given in a separate document.

Acoustic alarm output:

The output of the acoustic alarm takes place on vehicles without code (494) USA version by actuating the alarm siren and on vehicles with code 494 (USA version) by the left horn (H2) and right horn (H2/1).

The alarm siren is actuated by the rear SAM control unit via the SAM-LIN.

The horns are actuated by the front SAM control unit and horn relays (N10/1kO).

 The acoustic alarm is activated for t = 30 s and the optical alarm for t = 300 s.

On vehicles with code (833) Great Britain version, the acoustic alarm is extended to t = 300 s under the following conditions:

 Interruption of power lines

 If a door, the engine hood or trunk lid is broken open or remains open

 When the central locking (CL) is unlocked with the transmitter key or the transmitter key is inserted into the electronic ignition lock control unit (N73) the alarm output is interrupted.

The electronic ignition switch control unit transmits the corresponding signal with interior CAN to the rear SAM control unit, which then terminates the activated alarm.