Anti-theft alarm system trigger, function

Function requirements, general

 Antitheft alarm system (ATA) activated

 The electronic ignition lock control unit (N73) sends the status of the central locking (CL) to the rear SAM control unit with fuse and relay module (N10/2) via the interior CAN.

Anti-theft alarm system alarm triggering, general

If one of the alarm inputs of the activated ATA [EDW] exits its non-actuated state, an 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 drops below U  8.5 V, it is no longer possible to trigger a visual alarm output. Only an acoustic alarm is triggered. The battery voltage is stored in the ATA alarm memory in the rear SAM control unit.

The ATA [EDW] alarm triggering comprises the following subfunctions:

 Function sequence for actuating alarm by opening door, trunk lid or engine hood

 Function sequence for actuating alarm resulting from vehicle inclination (with code (882) Interior monitoring (only with ATA))

 Function sequence for actuating alarm resulting from motion in the passenger compartment (with code (882) Interior monitoring (only with ATA))

 Function sequence for actuating alarm resulting from communication loss to alarm siren(H3/1) (on model 207.3 up to 31.5.10, model 207.3 as of 1.6.10 without code (494) USA version, model 207.4 without code (494) USA version)

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

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

 Function sequence for alarm output

Function sequence for actuating alarm by opening door, trunk lid or engine hood

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:

 Engine hood switch pedestrian protection + ATA Hall sensor (A38/1) (with code (U60) Pedestrian protection)

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

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

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

 Left engine hood contact switch (S62/43) (without code (U60) Pedestrian protection)

The left front door control unit (N69/1) directly reads in the status of the left front door rotary tumbler switch and transmits it to the rear SAM control unit via the interior CAN (CAN B).

The right front door control unit (N69/2) directly reads in the status of the right front door rotary tumbler switch and transmits it to the rear SAM control unit via the interior CAN (CAN B).

The rear SAM control unit directly reads in the status of the trunk lid rotary tumbler switch or the status of the pedestrian protection Hall sensor + ATA [EDW] engine hood switch (with code (U60) pedestrian protection) or left engine hood contact switch (without code (U60) Pedestrian protection).

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 mechanical key and the door is opened, the ATA triggers an alarm.

Additional function requirements for alarm actuation by changing vehicle inclination (with code 882) Interior monitoring (only with ATA))

 Tow-away protection not deactivated

Function sequence for actuating alarm resulting from vehicle inclination (with code (882) Interior monitoring (only with ATA))

If the inclination sensor detects a change in inclination in the interior protection and tow-away protection control unit (N26/6) (model 207.3) or in the interior protection sensor (master) (A26/13) (model 207.4) around the horizontal axis of  = 1° to – 1° ( 0.2°), a corresponding signal is transmitted via the rear SAM-LIN (LIN B4) to the rear SAM control unit, which then triggers an alarm.

 If the vehicle is lifted before a wheel looses contact to the ground, an alarm is triggered.

Additional function requirements for alarm actuation by interior monitoring (with code (882) Interior monitoring (only with ATA))

 Interior protection not deactivated

Function sequence for actuating alarm resulting from motion in the passenger compartment (with code (882) Interior monitoring (only with ATA))

The interior compartment on model 207.3 is monitored by the interior protection and tow-away protection control unit with ultrasonic waves and on model 207.4 by the interior protection sensor (master) and interior protection sensor (slave) (A2615) with radar waves.

Model 207.3:

The left interior protection transmitter (N26/6b1) and the right interior protection transmitter (N26/6b2) send ultrasonic signals in the vehicle interior. The ultrasonic signals are received by the interior protection receiver (N26/6a1).

If a movement in the vehicle interior is recognized and considered to be alarm-relevant, an alarm is output. The interior protection and tow-away control unit transmits the request for the output of an ATA alarm via the interior CAN to the rear SAM control unit.

Model 207.4:

The interior protection sensors operate according to the master-slave principle. The interior protection sensor (Master) is located below the center console and monitors the front interior compartment. The Interior protection sensor (slave) is located below the rear stowage compartment and monitors the rear interior compartment. The interior protection sensor (master) evaluates all relevant data.

If the interior protection sensor (master) recognizes an alarm-relevant motion, it transmits a corresponding signal via the rear SAM-LIN to the rear SAM control unit, when then actuates an alarm.

 The sensitivity of the interior protection is reduced under the following circumstances:

 Side windows, panoramic roof (with code (413) Panoramic glass roof with top sliding roof) or softtop (model 207.4) opened or denormalized

 Active ventilation

 On vehicles with panoramic roof (with code (413) Panoramic glass sunroof top sliding roof) the interior compartment is not monitored during active rain closing. After closing or after expiration of t = 35 s, the interior protection is reactivated.

Function sequence for actuating alarm resulting from communication loss to alarm siren (on model 207.3 up to 31.5.10, model 207.3 as of 1.6.10 without code (494) USA version, model 207.4 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 a loss in the supply voltage, it also outputs an acoustic alarm automatically.

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

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

The trunk lid emergency opening switch (S88/10) 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.

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

Vehicles without code (889) KEYLESS-GO:

When the panic alarm button the transmitter key is actuated, it transmits a radio signal (access authorization) on model 207.3 via the rear window antenna (A2/32) and FM, AM und CL antenna amplifier (A2/18) or on model 207.4 via the windshield antenna (A2/118) and the FM, AM und CL antenna amplifier (A2/55) to the rear SAM control unit with fuse and relay module (N10/2). This relays the signal to the electronic ignition switch control unit with interior CAN.

Vehicles with code (889) KEYLESS-GO:

When the panic alarm button on the transmitter key is actuated, it transmits a radio signal (access authorization) on model 207.3 to the KEYLESS-GO control unit (N69/5) via the rear window antenna and FM, AM and CL antenna amplifier or on model 207.4 via the windshield antenna and FM, AM and CL antenna amplifier. The KEYLESS-GO control unit sends the radio signal (access authorization) to the electronic ignition lock control unit via interior CAN.

Parallel to the radio signal (access authorization), the transmitter key transmits an infrared signals via the driver door infrared remote control receiver (A26/1) (precise aiming required) and a direct line to the left front door control unit (N69/1). The left front door control unit transmits this to the electronic ignition lock control unit via the interior CAN.

In both cases the electronic ignition lock control unit checks the access authorization of the transmitter key.

If the access authorization is valid, the electronic ignition lock control unit transmits the "Activate panic alarm" request via the interior CAN to the rear SAM control unit. The rear SAM control unit actuates an ATA [EDW] alarm.

 The panic alarm is interrupted when the panic alarm button on the transmitter key is actuated briefly. The function sequence "Interrupting panic alarm" is the same as for "Actuating panic alarm".

Function sequence for alarm output

Visual alarm output

When an ATA alarm is triggered, the rear SAM control unit activates the hazard warning flasher function via interior CAN.

All turn signals are actuated synchronously on the vehicle.

 Detailed information on performing the hazard warning flasher function is included in the function description "Exterior lights, function" in the partial function "Turn signal light actuation, function".

In this case, the front SAM control unit with fuse and relay module (N10/1) switches on the interior illumination.

 Detailed information on performing the interior illumination function is included in the function description "Interior illumination, function" in the partial function "Automatic interior illumination function".

Acoustic alarm output

The alarm is output via the alarm siren (model 207.3 up to 31.5.10, model 207.3 as of 1.6.10 without code (494) USA version, model 207.4 without code (494) USA version) or left horn (H2) and right horn (H2/1) (model 207.3 as of 1.6.10 with code (494) USA version, model 207.4 with code (494) USA version).

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

The horns are actuated by the front SAM control unit via the horn relays (N101).

 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

 The alarm output is interrupted by opening the CL via infrared or radio or by switching on circuit 15C. The electronic ignition lock control unit transmits the status of the CL and the circuit status of circuit 15 to via the interior CAN to the rear SAM control unit, which terminates the active alarm.