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 to 16 V. No more visual or acoustic alarms can be output if the voltage drops to U  8 V.

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

 Function sequence for alarm triggering by opening a door, tailgate or engine hood

 Function sequence for alarm actuation by changing vehicle inclination (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for alarm triggering by motion in vehicle interior (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for alarm actuation from glass breakage (with code (882) Interior monitoring (only with ATA [EDW]))

 Function sequence for alarm triggering by communication loss to alarm siren (H3/1) (with code (882) Interior monitoring (only with ATA [EDW]))

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

 Function sequence for alarm output

Function sequence for alarm triggering by opening a door, tailgate or engine hood

The SAM control unit (N10) actuates an alarm so soon as the one of the following switches exits the non-actuated state:

 Left front door main catch microswitch (A85s2) in left front door lock (A85)

 Right front door main catch microswitch (A85/1s2) in right front door lock (A85/1)

 Left rear door main catch microswitch (A85/3s2) in left rear door lock (A85/3)

 Right rear door main catch microswitch (A85/4s2) in right rear door lock (A85/4)

 Liftgate rotary tumbler switch (M14/7s1) in liftgate central locking motor (M14/7)

 Left engine hood contact switch (S62/43)

The left front door control unit (N69/1) directly reads in the status of the left front door main catch microswitch and transmits it to the SAM control unit via interior CAN (CAN B).

The right front door control unit (N69/2) reads in the status of the right front door main catch microswitch directly and sends it to the SAM control unit via interior CAN.

The left rear door control unit (N69/3) directly reads in the status of the left rear door main catch microswitch and sends it via interior CAN to the SAM control unit.

The right rear door control unit (N69/4) directly reads in the status of the right rear door main catch microswitch and sends it via interior CAN to the SAM control unit.

The rear door control unit (N108) reads in the status of the liftgate rotary tumbler switch and transmits it to the SAM control unit over the interior CAN.

The SAM control unit directly reads in the status of the left engine hood contact switch.

The SAM control unit evaluates the status of all alarm inputs.

To trigger a new alarm, the corresponding switch must first change to the non-actuated state.

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 the door is opened, the ATA [EDW] triggers an alarm. The electronic ignition lock control unit (N73) transmits the status of the central locking (CL) to the SAM control unit via the interior CAN.

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

 Tow-away protection not deactivated

Function sequence for alarm actuation by changing vehicle inclination (with code (882) Interior monitoring (only with ATA [EDW]))

If the inclination sensor integrated into the ATA [EDW]/tow-away protection/interior protection control (N26/6) recognizes an alarm-related inclination change, an alarm is output.

The ATA/tow-away protection/interior protection control unit sends the request to output an ATA over the interior CAN to the SAM control unit.

Actuation criterion:

Changing of the vehicle inclination (on the horizontal axes) to approx.  1.2°

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

Additional function requirements for alarm triggering by motion in vehicle interior (with code (882) Interior monitoring (only with ATA [EDW]))

 Interior protection not deactivated

Function sequence for alarm triggering by motion in vehicle interior (with code (882) Interior monitoring (only with ATA [EDW]))

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 ATA/tow-away protection/interior protection control unit sends the request to output an ATA over the interior CAN to the SAM control unit.

The sensitivity of the interior protection is reduced depending on the following conditions:

 Side window, sliding roof (with code (414) Power glass tilting/sliding roof) or panoramic sliding sunroof (with code (413) Panoramic glass sunroof with top sliding sunroof) open or normalized

 Active ventilation

 MODEL 166
up to model year 2016
with CODE 413 (Panoramic glass roof with top sliding roof)
with CODE 551 (Anti-theft alarm system)
MODEL 166
up to model year 2016
with CODE 414 (Power glass tilting/sliding roof)
with CODE 551 (Anti-theft alarm system)
The vehicle interior is not monitored during active rain closing. After closing or after expiration of t = 35 s, the interior protection is reactivated.

 MODEL 166
up to model year 2016
with CODE 551 (Anti-theft alarm system)
with CODE 890 (EASY-PACK liftgate)
When the liftgate is opened with the transmitter key (A8/1) the interior protection is deactivated. The interior protection is activated during comfort closing, however, the interior compartment is not monitored.

Function sequence for alarm actuation from glass breakage (with code (882) Interior monitoring (only with ATA [EDW]))

The ATA [EDW]/tow-away protection/interior protection control monitors the status of the following sensors:

 Left rear window glass breakage sensor (B39)

 Right rear window glass breakage sensor (B39/1)

 Rear window glass breakage sensor (B39/4)

If the (EDW/tow-away protection/interior protection) control unit detects an interrupt in the contact loop in the glass in the rear side window or rear hatch, an alarm is triggered.

The ATA/tow-away protection/interior protection control unit sends the request to output an ATA over the interior CAN to the SAM control unit.

 After an alarm is triggered by a glass breakage sensor, the other glass breakage sensors are deactivated (series circuit).

Function sequence for alarm triggering by communication loss to alarm siren (with code (882) Interior monitoring (only with ATA [EDW]))

The alarm siren is actuated cyclically approx. every t = 600 ms by the ATA [EDW]/tow-away protection/interior protection control via the alarm system LIN (LIN B14). If a reply to this request is not received within t = 1 s by the alarm siren (no communication), the ATA [EDW]/tow-away protection/interior protection control trigger an alarm.

The ATA/tow-away protection/interior protection control unit sends the request to output an ATA over the interior CAN to the SAM control unit.

If the alarm siren detects a loss of supply voltage, it also automatically emits an acoustic alarm.

 An alarm is only repeated if a new alarm event is registered after the active acoustic alarm was terminated. Three or ten alarms can be output during an arming cycle depending on the national version.

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

Vehicles except CODE 889 (KEYLESS-GO):

When the panic alarm button on the transmitter key is pressed for t  2 s, it sends a radio signal (access authorization code) over the rear window antenna (A2/32) and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18) to the electronic ignition lock control unit.

Vehicles with CODE 889 (KEYLESS-GO)

When the panic alarm button on the transmitter key is pressed for t  2 s, it sends a radio signal (access authorization code) over the rear window antenna and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier to the KEYLESS-GO control unit (N69/5). The KEYLESS GO control unit transmits the access authorization code to the electronic ignition lock control unit via interior CAN.

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

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

The electronic ignition switch 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 SAM control unit. The 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.

Function sequence for alarm output

Visual alarm output

When an ATA alarm is triggered, the 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".

Moreover, the SAM control unit switches on the interior illumination.

 Detailed information on implementation of the interior illumination is given in the function description "Interior illumination (IBL) function".

Acoustic alarm output

The acoustic alarm is output on vehicles with code (882) Interior monitoring (only with ATA [EDW]) by actuating the alarm siren and on vehicles except code (882) Interior monitoring (only with ATA [EDW]) by actuating the left horn (H2) and right horn (H2/1).

The alarm siren is actuated by the ATA/tow-away protection/interior protection control unit via the alarm system LIN.

The horns are actuated by the SAM control unit via the horn relays (F58kJ).

 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 liftgate 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 SAM control unit, which terminates the active alarm.